fix: incorrect buying amount in Gross Profit rpt
diff --git a/erpnext/accounts/report/gross_profit/gross_profit.py b/erpnext/accounts/report/gross_profit/gross_profit.py
index 526ea9d..54af225 100644
--- a/erpnext/accounts/report/gross_profit/gross_profit.py
+++ b/erpnext/accounts/report/gross_profit/gross_profit.py
@@ -616,7 +616,7 @@
 						previous_stock_value = len(my_sle) > i + 1 and flt(my_sle[i + 1].stock_value) or 0.0
 
 						if previous_stock_value:
-							return (previous_stock_value - flt(sle.stock_value)) * flt(row.qty) / abs(flt(sle.qty))
+							return abs(previous_stock_value - flt(sle.stock_value)) * flt(row.qty) / abs(flt(sle.qty))
 						else:
 							return flt(row.qty) * self.get_average_buying_rate(row, item_code)
 			else: