store_costing_bill_details

Using GREATEST(0,estimate_tran_cost_rate) and
GREATEST(0,estimate_tran_cost_amount) to ensure that the -1 prices in
case of custom products do not affect the margin calculations
store_costing_store_details

Using GREATEST(0,estimate_tran_cost_rate) and
GREATEST(0,estimate_tran_cost_amount) to ensure that the -1 prices in
case of custom products do not affect the margin calculations
store_costing_update

Using GREATEST(0,estimate_tran_cost_rate) and
GREATEST(0,estimate_tran_cost_amount) to ensure that the -1 prices in
case of custom products do not affect the margin calculations