The General Ledger Setup Table
Click to enter a check mark in this field if you want the program to recalculate tax amounts when you post payments that trigger payment discounts.
By clicking this field you enable the feature in general. To use the feature, you must activate it in the Adjust for Payment Discount field for those combinations in the VAT posting setup that you want to use it for.
Note that you cannot use the adjust for payment discount option if you have inserted a check mark in the Pmt. Disc. Excl. VAT field (this would not make sense, because if VAT has not been calculated on a payment discount, there is no need for adjustment).