fix: Create Depreciation Schedules for existing Assets accurately (#28675)

erpnext/assets/doctype/asset/asset.py

@@ -192,8 +192,7 @@ class Asset(AccountsController):
 
 			# value_after_depreciation - current Asset value
 			if self.docstatus == 1 and d.value_after_depreciation:
-				value_after_depreciation = (flt(d.value_after_depreciation) -
-					flt(self.opening_accumulated_depreciation))
+				value_after_depreciation = flt(d.value_after_depreciation)
 			else:
 				value_after_depreciation = (flt(self.gross_purchase_amount) -
 					flt(self.opening_accumulated_depreciation))
@@ -241,7 +240,7 @@ class Asset(AccountsController):
 					break
 
 				# For first row
-				if has_pro_rata and n==0:
+				if has_pro_rata and not self.opening_accumulated_depreciation and n==0:
 					depreciation_amount, days, months = self.get_pro_rata_amt(d, depreciation_amount,
 						self.available_for_use_date, d.depreciation_start_date)
 
@@ -254,7 +253,7 @@ class Asset(AccountsController):
 					if not self.flags.increase_in_asset_life:
 						# In case of increase_in_asset_life, the self.to_date is already set on asset_repair submission
 						self.to_date = add_months(self.available_for_use_date,
-							n * cint(d.frequency_of_depreciation))
+							(n + self.number_of_depreciations_booked) * cint(d.frequency_of_depreciation))
 
 					depreciation_amount_without_pro_rata = depreciation_amount
 
@@ -354,7 +353,12 @@ class Asset(AccountsController):
 	# if it returns True, depreciation_amount will not be equal for the first and last rows
 	def check_is_pro_rata(self, row):
 		has_pro_rata = False
-		days = date_diff(row.depreciation_start_date, self.available_for_use_date) + 1
+
+		# if not existing asset, from_date = available_for_use_date
+		# otherwise, if number_of_depreciations_booked = 2, available_for_use_date = 01/01/2020 and frequency_of_depreciation = 12
+		# from_date = 01/01/2022
+		from_date = self.get_modified_available_for_use_date(row)
+		days = date_diff(row.depreciation_start_date, from_date) + 1
 
 		# if frequency_of_depreciation is 12 months, total_days = 365
 		total_days = get_total_days(row.depreciation_start_date, row.frequency_of_depreciation)
@@ -364,6 +368,9 @@ class Asset(AccountsController):
 
 		return has_pro_rata
 
+	def get_modified_available_for_use_date(self, row):
+		return add_months(self.available_for_use_date, (self.number_of_depreciations_booked * row.frequency_of_depreciation))
+
 	def validate_asset_finance_books(self, row):
 		if flt(row.expected_value_after_useful_life) >= flt(self.gross_purchase_amount):
 			frappe.throw(_("Row {0}: Expected Value After Useful Life must be less than Gross Purchase Amount")
@@ -402,10 +409,11 @@ class Asset(AccountsController):
 
 	# to ensure that final accumulated depreciation amount is accurate
 	def get_adjusted_depreciation_amount(self, depreciation_amount_without_pro_rata, depreciation_amount_for_last_row, finance_book):
-		depreciation_amount_for_first_row = self.get_depreciation_amount_for_first_row(finance_book)
+		if not self.opening_accumulated_depreciation:
+			depreciation_amount_for_first_row = self.get_depreciation_amount_for_first_row(finance_book)
 
-		if depreciation_amount_for_first_row + depreciation_amount_for_last_row != depreciation_amount_without_pro_rata:
-			depreciation_amount_for_last_row = depreciation_amount_without_pro_rata - depreciation_amount_for_first_row
+			if depreciation_amount_for_first_row + depreciation_amount_for_last_row != depreciation_amount_without_pro_rata:
+				depreciation_amount_for_last_row = depreciation_amount_without_pro_rata - depreciation_amount_for_first_row
 
 		return depreciation_amount_for_last_row
 
@@ -850,13 +858,11 @@ def get_total_days(date, frequency):
 
 @erpnext.allow_regional
 def get_depreciation_amount(asset, depreciable_value, row):
-	depreciation_left = flt(row.total_number_of_depreciations) - flt(asset.number_of_depreciations_booked)
-
 	if row.depreciation_method in ("Straight Line", "Manual"):
 		# if the Depreciation Schedule is being prepared for the first time
 		if not asset.flags.increase_in_asset_life:
-			depreciation_amount = (flt(asset.gross_purchase_amount) - flt(asset.opening_accumulated_depreciation) -
-				flt(row.expected_value_after_useful_life)) / depreciation_left
+			depreciation_amount = (flt(asset.gross_purchase_amount) -
+				flt(row.expected_value_after_useful_life)) / flt(row.total_number_of_depreciations)
 
 		# if the Depreciation Schedule is being modified after Asset Repair
 		else:

erpnext/assets/doctype/asset/test_asset.py

@@ -409,19 +409,18 @@ class TestDepreciationMethods(AssetSetup):
 			calculate_depreciation = 1,
 			available_for_use_date = "2030-06-06",
 			is_existing_asset = 1,
-			number_of_depreciations_booked = 1,
-			opening_accumulated_depreciation = 40000,
+			number_of_depreciations_booked = 2,
+			opening_accumulated_depreciation = 47095.89,
 			expected_value_after_useful_life = 10000,
-			depreciation_start_date = "2030-12-31",
+			depreciation_start_date = "2032-12-31",
 			total_number_of_depreciations = 3,
 			frequency_of_depreciation = 12
 		)
 
 		self.assertEqual(asset.status, "Draft")
 		expected_schedules = [
-			["2030-12-31", 14246.58, 54246.58],
-			["2031-12-31", 25000.00, 79246.58],
-			["2032-06-06", 10753.42, 90000.00]
+			["2032-12-31", 30000.0, 77095.89],
+			["2033-06-06", 12904.11, 90000.0]
 		]
 		schedules = [[cstr(d.schedule_date), flt(d.depreciation_amount, 2), d.accumulated_depreciation_amount]
 			for d in asset.get("schedules")]

erpnext/regional/india/utils.py

@@ -847,13 +847,11 @@ def update_taxable_values(doc, method):
 		doc.get('items')[item_count - 1].taxable_value += diff
 
 def get_depreciation_amount(asset, depreciable_value, row):
-	depreciation_left = flt(row.total_number_of_depreciations) - flt(asset.number_of_depreciations_booked)
-
 	if row.depreciation_method in ("Straight Line", "Manual"):
 		# if the Depreciation Schedule is being prepared for the first time
 		if not asset.flags.increase_in_asset_life:
-			depreciation_amount = (flt(asset.gross_purchase_amount) - flt(asset.opening_accumulated_depreciation) -
-				flt(row.expected_value_after_useful_life)) / depreciation_left
+			depreciation_amount = (flt(asset.gross_purchase_amount) -
+				flt(row.expected_value_after_useful_life)) / flt(row.total_number_of_depreciations)
 
 		# if the Depreciation Schedule is being modified after Asset Repair
 		else: