Amount rounding on invoice and credit memo

NaviDev

Im in a very strange situation right now. We have a transaction in the purchase invoice for this amounts of 28,054.89, 506.16 and 21,215.63 inclusive of vats 12%. Automatically Nav computed like this

25,049.01 - Exclusive of vat
3,005.88 - Vat Amount

451.93 - Exclusive of vat
54.23 - Vat Amount

18,942.52 - Exclusive of vat
2,273.11 - Vat Amount


When I do credit memo to reverse this invoice using the purchase journal. Nav computed like this

25,049.01 - Exclusive of Vat
3,005.88 - Vat Amount

451.93 - Exclusive of vat
54.23 - Vat Amount

18,942.53 - Exclusive of vat
2,273.10 - Vat Amount

Notice that the amount in the invoice third line and credit memo third line are different.

I am using 4.03. My GL Setup Invoice Rounding Precision is set to 0.01. Why am I getting this different figures? ](*,)[/b]