Stock Card: Percentage Profit Margin

A new feature has been added to Stock Card, which calculates the percentage profit margin for the current Root PLU.

The percentage profit margin is calculated as follows.

Variables
 CostPrice   = 10.00
 RetailPrice = 20.00
 VATRate     = 17.5%

Calculate BeforeVAT
 BeforeVAT   = RetailPrice / ( 1 + (VATRate/100))
 BeforeVAT   = 20.00 / ( 1 + (17.5/100))
 BeforeVAT   = 17.02128

Calculate Profit
 Profit      = BeforeVAT - CostPrice
 Profit      = 7.02128

Calculate Percentage Profit Margin
 PerProfit   = (Profit / BeforeVAT) * 100
 PerProfit   = (7.02128 / 17.02128) * 100
 PerProfit   = 0.4125 * 100
 PerProfit   = 41.25%