fix: Get pro-rata depr amount based on correct days

erpnext/assets/doctype/asset/asset.py

@@ -437,6 +437,7 @@ class Asset(AccountsController):
 					depreciation_amount,
 					from_date,
 					date_of_disposal,
+					original_schedule_date=schedule_date,
 				)
 
 				if depreciation_amount > 0:
@@ -1118,14 +1119,20 @@ class Asset(AccountsController):
 			return flt((100 * (1 - depreciation_rate)), float_precision)
 
 	def get_pro_rata_amt(
-		self, row, depreciation_amount, from_date, to_date, has_wdv_or_dd_non_yearly_pro_rata=False
+		self,
+		row,
+		depreciation_amount,
+		from_date,
+		to_date,
+		has_wdv_or_dd_non_yearly_pro_rata=False,
+		original_schedule_date=None,
 	):
 		days = date_diff(to_date, from_date)
 		months = month_diff(to_date, from_date)
 		if has_wdv_or_dd_non_yearly_pro_rata:
-			total_days = get_total_days(to_date, 12)
+			total_days = get_total_days(original_schedule_date or to_date, 12)
 		else:
-			total_days = get_total_days(to_date, row.frequency_of_depreciation)
+			total_days = get_total_days(original_schedule_date or to_date, row.frequency_of_depreciation)
 
 		return (depreciation_amount * flt(days)) / flt(total_days), days, months
 
@@ -1445,32 +1452,35 @@ def get_straight_line_or_manual_depr_amount(
 	# if the Depreciation Schedule is being modified after Asset Value Adjustment due to decrease in asset value
 	elif asset.flags.decrease_in_asset_value_due_to_value_adjustment:
 		if row.daily_prorata_based:
-			daily_depr_amount = (
+			amount = flt(row.value_after_depreciation) - flt(row.expected_value_after_useful_life)
-				flt(row.value_after_depreciation) - flt(row.expected_value_after_useful_life)
+			total_days = (
-			) / date_diff(
+				date_diff(
-				get_last_day(
-					add_months(
-						row.depreciation_start_date,
-						flt(row.total_number_of_depreciations - asset.number_of_depreciations_booked - 1)
-						* row.frequency_of_depreciation,
-					)
-				),
-				add_days(
 					get_last_day(
 						add_months(
 							row.depreciation_start_date,
-							flt(
+							flt(row.total_number_of_depreciations - asset.number_of_depreciations_booked - 1)
-								row.total_number_of_depreciations
-								- asset.number_of_depreciations_booked
-								- number_of_pending_depreciations
-								- 1
-							)
 							* row.frequency_of_depreciation,
 						)
 					),
-					1,
+					add_days(
-				),
+						get_last_day(
+							add_months(
+								row.depreciation_start_date,
+								flt(
+									row.total_number_of_depreciations
+									- asset.number_of_depreciations_booked
+									- number_of_pending_depreciations
+									- 1
+								)
+								* row.frequency_of_depreciation,
+							)
+						),
+						1,
+					),
+				)
+				+ 1
 			)
+			daily_depr_amount = amount / total_days
 
 			to_date = get_last_day(
 				add_months(row.depreciation_start_date, schedule_idx * row.frequency_of_depreciation)
@@ -1490,22 +1500,28 @@ def get_straight_line_or_manual_depr_amount(
 	# if the Depreciation Schedule is being prepared for the first time
 	else:
 		if row.daily_prorata_based:
-			daily_depr_amount = (
+
+			amount = (
 				flt(asset.gross_purchase_amount)
 				- flt(asset.opening_accumulated_depreciation)
 				- flt(row.expected_value_after_useful_life)
-			) / date_diff(
-				get_last_day(
-					add_months(
-						row.depreciation_start_date,
-						flt(row.total_number_of_depreciations - asset.number_of_depreciations_booked - 1)
-						* row.frequency_of_depreciation,
-					)
-				),
-				add_days(
-					get_last_day(add_months(row.depreciation_start_date, -1 * row.frequency_of_depreciation)), 1
-				),
 			)
+			total_days = (
+				date_diff(
+					get_last_day(
+						add_months(
+							row.depreciation_start_date,
+							flt(row.total_number_of_depreciations - asset.number_of_depreciations_booked - 1)
+							* row.frequency_of_depreciation,
+						)
+					),
+					add_days(
+						get_last_day(add_months(row.depreciation_start_date, -1 * row.frequency_of_depreciation)), 1
+					),
+				)
+				+ 1
+			)
+			daily_depr_amount = amount / total_days
 
 			to_date = get_last_day(
 				add_months(row.depreciation_start_date, schedule_idx * row.frequency_of_depreciation)

erpnext/assets/doctype/asset/test_asset.py

@@ -219,7 +219,11 @@ class TestAsset(AssetSetup):
 			asset.precision("gross_purchase_amount"),
 		)
 		pro_rata_amount, _, _ = asset.get_pro_rata_amt(
-			asset.finance_books[0], 9000, get_last_day(add_months(purchase_date, 1)), date
+			asset.finance_books[0],
+			9000,
+			get_last_day(add_months(purchase_date, 1)),
+			date,
+			original_schedule_date=get_last_day(nowdate()),
 		)
 		pro_rata_amount = flt(pro_rata_amount, asset.precision("gross_purchase_amount"))
 		self.assertEquals(
@@ -287,7 +291,11 @@ class TestAsset(AssetSetup):
 		self.assertEqual(frappe.db.get_value("Asset", asset.name, "status"), "Sold")
 
 		pro_rata_amount, _, _ = asset.get_pro_rata_amt(
-			asset.finance_books[0], 9000, get_last_day(add_months(purchase_date, 1)), date
+			asset.finance_books[0],
+			9000,
+			get_last_day(add_months(purchase_date, 1)),
+			date,
+			original_schedule_date=get_last_day(nowdate()),
 		)
 		pro_rata_amount = flt(pro_rata_amount, asset.precision("gross_purchase_amount"))
 
@@ -349,7 +357,7 @@ class TestAsset(AssetSetup):
 
 		self.assertEqual(frappe.db.get_value("Asset", asset.name, "status"), "Sold")
 
-		expected_values = [["2023-03-31", 12000, 36000], ["2023-05-23", 1742.47, 37742.47]]
+		expected_values = [["2023-03-31", 12000, 36000], ["2023-05-23", 1737.7, 37737.7]]
 
 		for i, schedule in enumerate(asset.schedules):
 			self.assertEqual(getdate(expected_values[i][0]), schedule.schedule_date)
@@ -360,7 +368,7 @@ class TestAsset(AssetSetup):
 		expected_gle = (
 			(
 				"_Test Accumulated Depreciations - _TC",
-				37742.47,
+				37737.7,
 				0.0,
 			),
 			(
@@ -371,7 +379,7 @@ class TestAsset(AssetSetup):
 			(
 				"_Test Gain/Loss on Asset Disposal - _TC",
 				0.0,
-				17742.47,
+				17737.7,
 			),
 			("Debtors - _TC", 40000.0, 0.0),
 		)
@@ -691,18 +699,18 @@ class TestDepreciationMethods(AssetSetup):
 		)
 
 		expected_schedules = [
-			["2023-01-31", 1021.98, 1021.98],
+			["2023-01-31", 1019.18, 1019.18],
-			["2023-02-28", 923.08, 1945.06],
+			["2023-02-28", 920.55, 1939.73],
-			["2023-03-31", 1021.98, 2967.04],
+			["2023-03-31", 1019.18, 2958.91],
-			["2023-04-30", 989.01, 3956.05],
+			["2023-04-30", 986.3, 3945.21],
-			["2023-05-31", 1021.98, 4978.03],
+			["2023-05-31", 1019.18, 4964.39],
-			["2023-06-30", 989.01, 5967.04],
+			["2023-06-30", 986.3, 5950.69],
-			["2023-07-31", 1021.98, 6989.02],
+			["2023-07-31", 1019.18, 6969.87],
-			["2023-08-31", 1021.98, 8011.0],
+			["2023-08-31", 1019.18, 7989.05],
-			["2023-09-30", 989.01, 9000.01],
+			["2023-09-30", 986.3, 8975.35],
-			["2023-10-31", 1021.98, 10021.99],
+			["2023-10-31", 1019.18, 9994.53],
-			["2023-11-30", 989.01, 11011.0],
+			["2023-11-30", 986.3, 10980.83],
-			["2023-12-31", 989.0, 12000.0],
+			["2023-12-31", 1019.17, 12000.0],
 		]
 
 		schedules = [