TAX SHOULD BE CALCULATED IN THE INVOICE BILL
EXAMPLE (PROMOTION BUY 2 GET 1 FREE) PROMOTION
THE TAX SHOULD BE CALCULATED INCLUDING GET 1 FREE ITEM ALSO\
EXAMPLE BUY 2 GET 1 FREE
1000*2 = 2000
GET 1 FREE 1000
TAX SHOULD BE CALCULATED INCLUDING THE FREE AMOUNT ALSO
Guest
Use "Apportion discount to all items" option while defining promo.
In your case, the Rs. 1000 discount will be apportioned to all 3 items, each item being 666.66, then tax will be calculated in all 3 items on 666.66 (be it inclusive or exclusive).