You can record the increase in output tax as Cash Discount on Sales by the creating a journal voucher for the same.
To account for increase in output tax
1. Go to Gateway of Tally > Accounting Vouchers > F7: Journal.
2. Click J: Stat Adjustment to enable the required options in the Stat Adjustment Details screen.
3. Debit the sales ledger and enter the assessable value.
4. Debit the output VAT ledger. Enter the Rate, Surcharge Rate and Assessable Value in VAT Details screen. Enter the tax amount.
5. Debit the surcharge ledger. Enter the Rate, Surcharge Rate and Assessable Value in VAT Details screen. Enter the tax amount.
6. Credit the party ledger. The journal voucher appears as shown below:
7. Press Enter to save.