How to set automatic rounding off in tally ERP9

http://tallygame.com/tally-erp-9/tally-advanced/automatic-round-off-in-tally-erp9/ how to set automatic rounding off in tally ERP9,What is rounding off ,types of rounding off , the method to create round off in tally explained in this lesson ,Read more about automatic rounding off

Comments

1. If i use the rounding off option VAT gets disabled, even though it has been activated. How to use roundingoff feature with VAT calculation.
2. how to enable VAT here?