TDS Amount Rs.1 in Vendor Invoice for all

Dear Experts,

we have 2 vendors while i making invoice in f-43 for a X vendor the with holding TDS 1% is calculating properly without manual input for the grand amount.

in the same case with the vendor Y TDS have 2 % , Withholding tax amount is not calculating default its come as Rs.1.

i checked for the both vendor master data and configuration all are same. but why its coming as rs.1 . kindly suggest me.

Prince.