GST on Coupon Discount for B2B Invoice in GSTR-1

This is a B2B Invoice. How to file "tax" details for this invoice in GSTR -1 Table 4:

Without applying 5% coupon Discount, the values are as follows:

Total Invoice Amt : 699
Taxable Value : 624.11
Tax/ IGST : 74.89

After applying 5% Coupon Discount of Rs. 34.95 (31.21 taxable value + 3.74 tax), the values are:

Invoice Amt: 664.05
Taxable Value : 592.90
Tax/ IGST : 71.15

As per GST Act, we have to pay tax on coupon offered. How to adjust tax amount of Rs. 3.74 in GSTR-1? If we add back the discount amt, then buyer will claim extra ITC to that extend.