There is an option in WHT customization to maintain minimum base amount as per withholding tax code. As we are going live in the middle of year so we want to maintain it at vendor level.
Minimum base amount maintained at 40000
Vendor 1 Total Purchasing till Go Live date = 38000
Vendor 2 Total Purchasing till Go Live date = 20000
Hence, if we set minimum base amount at tax code level, all the purchasing after Go live will not consider previous purchases till go live..