Calculate Taxes button
Click the Calculate Taxes button if you want to see tax amounts for a detail before you have posted the receipt or opened the Totals tab. (Tax amounts are not automatically calculated until you choose Post for the receipt or click the Taxes tab or Totals tab.)
If you edit tax amounts on the Taxes tab, then use the Calculate Taxes button, the program will replace your changes with amounts it calculates using the tax tables in Tax Services.