Apply Housing Benefit accommodation disregards from their start date

changelog.d/hb-accommodation-dates.fixed.md

@@ -0,0 +1 @@
+- Applied Housing Benefit accommodation earnings disregards from their statutory commencement within the first fiscal year, calculating awards before combining date segments.

policyengine_uk/parameters/gov/dwp/housing_benefit/means_test/income_disregard/specified_or_temporary_accommodation/couple/minors.yaml

@@ -3,15 +3,13 @@ values:
   # Schedule 4 paragraph 18 (NI: Schedule 5 paragraph 18) has effect from 5
   # October 2026: SI 2026/753 reg. 2(4), as substituted by SI 2026/978 reg.
   # 2(2), and NI SR 2026/157 reg. 2(4). There was no such disregard before.
-  # Neither instrument uprates the sums. The model reads each fiscal year at
-  # 30 April, so 2026 (2026-27) has no paragraph 18 disregard although it
-  # applied from 5 October 2026 (183 of the year's 365 days); 2027 onwards
-  # has the full amounts. fiscal_year_blend is not used: half of an amount
-  # for the whole year is not the full amount for half the year, because
-  # the disregard is capped at net earnings and counts in the £17.10 test.
+  # Neither instrument uprates the sums. Preserve the legal date so awards
+  # can be calculated separately before/after commencement, including the
+  # earnings cap and additional-disregard test, then combined over the year.
   2006-03-06: 0
   2026-10-05: 97.33
 metadata:
+  preserve_calendar_dates: true
   period: week
   unit: currency-GBP
   label: Housing benefit specified or temporary accommodation earnings disregard, couple both under 18

policyengine_uk/parameters/gov/dwp/housing_benefit/means_test/income_disregard/specified_or_temporary_accommodation/couple/older.yaml

@@ -3,15 +3,13 @@ values:
   # Schedule 4 paragraph 18 (NI: Schedule 5 paragraph 18) has effect from 5
   # October 2026: SI 2026/753 reg. 2(4), as substituted by SI 2026/978 reg.
   # 2(2), and NI SR 2026/157 reg. 2(4). There was no such disregard before.
-  # Neither instrument uprates the sums. The model reads each fiscal year at
-  # 30 April, so 2026 (2026-27) has no paragraph 18 disregard although it
-  # applied from 5 October 2026 (183 of the year's 365 days); 2027 onwards
-  # has the full amounts. fiscal_year_blend is not used: half of an amount
-  # for the whole year is not the full amount for half the year, because
-  # the disregard is capped at net earnings and counts in the £17.10 test.
+  # Neither instrument uprates the sums. Preserve the legal date so awards
+  # can be calculated separately before/after commencement, including the
+  # earnings cap and additional-disregard test, then combined over the year.
   2006-03-06: 0
   2026-10-05: 119.7
 metadata:
+  preserve_calendar_dates: true
   period: week
   unit: currency-GBP
   label: Housing benefit specified or temporary accommodation earnings disregard, couple with one member 25 or over

policyengine_uk/parameters/gov/dwp/housing_benefit/means_test/income_disregard/specified_or_temporary_accommodation/couple/younger.yaml

@@ -3,15 +3,13 @@ values:
   # Schedule 4 paragraph 18 (NI: Schedule 5 paragraph 18) has effect from 5
   # October 2026: SI 2026/753 reg. 2(4), as substituted by SI 2026/978 reg.
   # 2(2), and NI SR 2026/157 reg. 2(4). There was no such disregard before.
-  # Neither instrument uprates the sums. The model reads each fiscal year at
-  # 30 April, so 2026 (2026-27) has no paragraph 18 disregard although it
-  # applied from 5 October 2026 (183 of the year's 365 days); 2027 onwards
-  # has the full amounts. fiscal_year_blend is not used: half of an amount
-  # for the whole year is not the full amount for half the year, because
-  # the disregard is capped at net earnings and counts in the £17.10 test.
+  # Neither instrument uprates the sums. Preserve the legal date so awards
+  # can be calculated separately before/after commencement, including the
+  # earnings cap and additional-disregard test, then combined over the year.
   2006-03-06: 0
   2026-10-05: 61.53
 metadata:
+  preserve_calendar_dates: true
   period: week
   unit: currency-GBP
   label: Housing benefit specified or temporary accommodation earnings disregard, couple both under 25, one 18 or over

policyengine_uk/parameters/gov/dwp/housing_benefit/means_test/income_disregard/specified_or_temporary_accommodation/lone_parent/older.yaml

@@ -3,15 +3,13 @@ values:
   # Schedule 4 paragraph 18 (NI: Schedule 5 paragraph 18) has effect from 5
   # October 2026: SI 2026/753 reg. 2(4), as substituted by SI 2026/978 reg.
   # 2(2), and NI SR 2026/157 reg. 2(4). There was no such disregard before.
-  # Neither instrument uprates the sums. The model reads each fiscal year at
-  # 30 April, so 2026 (2026-27) has no paragraph 18 disregard although it
-  # applied from 5 October 2026 (183 of the year's 365 days); 2027 onwards
-  # has the full amounts. fiscal_year_blend is not used: half of an amount
-  # for the whole year is not the full amount for half the year, because
-  # the disregard is capped at net earnings and counts in the £17.10 test.
+  # Neither instrument uprates the sums. Preserve the legal date so awards
+  # can be calculated separately before/after commencement, including the
+  # earnings cap and additional-disregard test, then combined over the year.
   2006-03-06: 0
   2026-10-05: 77.73
 metadata:
+  preserve_calendar_dates: true
   period: week
   unit: currency-GBP
   label: Housing benefit specified or temporary accommodation earnings disregard, lone parent aged 25 or over

policyengine_uk/parameters/gov/dwp/housing_benefit/means_test/income_disregard/specified_or_temporary_accommodation/lone_parent/younger.yaml

@@ -3,15 +3,13 @@ values:
   # Schedule 4 paragraph 18 (NI: Schedule 5 paragraph 18) has effect from 5
   # October 2026: SI 2026/753 reg. 2(4), as substituted by SI 2026/978 reg.
   # 2(2), and NI SR 2026/157 reg. 2(4). There was no such disregard before.
-  # Neither instrument uprates the sums. The model reads each fiscal year at
-  # 30 April, so 2026 (2026-27) has no paragraph 18 disregard although it
-  # applied from 5 October 2026 (183 of the year's 365 days); 2027 onwards
-  # has the full amounts. fiscal_year_blend is not used: half of an amount
-  # for the whole year is not the full amount for half the year, because
-  # the disregard is capped at net earnings and counts in the £17.10 test.
+  # Neither instrument uprates the sums. Preserve the legal date so awards
+  # can be calculated separately before/after commencement, including the
+  # earnings cap and additional-disregard test, then combined over the year.
   2006-03-06: 0
   2026-10-05: 61.41
 metadata:
+  preserve_calendar_dates: true
   period: week
   unit: currency-GBP
   label: Housing benefit specified or temporary accommodation earnings disregard, lone parent under 25

policyengine_uk/parameters/gov/dwp/housing_benefit/means_test/income_disregard/specified_or_temporary_accommodation/single/older.yaml

@@ -3,15 +3,13 @@ values:
   # Schedule 4 paragraph 18 (NI: Schedule 5 paragraph 18) has effect from 5
   # October 2026: SI 2026/753 reg. 2(4), as substituted by SI 2026/978 reg.
   # 2(2), and NI SR 2026/157 reg. 2(4). There was no such disregard before.
-  # Neither instrument uprates the sums. The model reads each fiscal year at
-  # 30 April, so 2026 (2026-27) has no paragraph 18 disregard although it
-  # applied from 5 October 2026 (183 of the year's 365 days); 2027 onwards
-  # has the full amounts. fiscal_year_blend is not used: half of an amount
-  # for the whole year is not the full amount for half the year, because
-  # the disregard is capped at net earnings and counts in the £17.10 test.
+  # Neither instrument uprates the sums. Preserve the legal date so awards
+  # can be calculated separately before/after commencement, including the
+  # earnings cap and additional-disregard test, then combined over the year.
   2006-03-06: 0
   2026-10-05: 77.73
 metadata:
+  preserve_calendar_dates: true
   period: week
   unit: currency-GBP
   label: Housing benefit specified or temporary accommodation earnings disregard, single claimant aged 25 or over

policyengine_uk/parameters/gov/dwp/housing_benefit/means_test/income_disregard/specified_or_temporary_accommodation/single/younger.yaml

@@ -3,15 +3,13 @@ values:
   # Schedule 4 paragraph 18 (NI: Schedule 5 paragraph 18) has effect from 5
   # October 2026: SI 2026/753 reg. 2(4), as substituted by SI 2026/978 reg.
   # 2(2), and NI SR 2026/157 reg. 2(4). There was no such disregard before.
-  # Neither instrument uprates the sums. The model reads each fiscal year at
-  # 30 April, so 2026 (2026-27) has no paragraph 18 disregard although it
-  # applied from 5 October 2026 (183 of the year's 365 days); 2027 onwards
-  # has the full amounts. fiscal_year_blend is not used: half of an amount
-  # for the whole year is not the full amount for half the year, because
-  # the disregard is capped at net earnings and counts in the £17.10 test.
+  # Neither instrument uprates the sums. Preserve the legal date so awards
+  # can be calculated separately before/after commencement, including the
+  # earnings cap and additional-disregard test, then combined over the year.
   2006-03-06: 0
   2026-10-05: 61.41
 metadata:
+  preserve_calendar_dates: true
   period: week
   unit: currency-GBP
   label: Housing benefit specified or temporary accommodation earnings disregard, single claimant under 25