RTN invoice is getting created with the less amount.

Hi Team, I have a standard invoice with amount 250000 which has 10% TDS i.e 25000, Then I have applied the prepayment of 77600 rs., RTN invoice of 7600

rs (10% DS rate) created, but when I again applied the prepayment of remaining 172400, it created RTN invoice of only 11889 got created which is not 10% of prepayment invoice.

1- in all standard and prepayment invoice TDS rate is 10%

2- second prepayment invoice was just a part of high prepayment invoice, just some part of that invoice is applied in this standard invoice.

Please share your opinion about this issue.