Tax code rounding off issue in AX 2012

Hi,

I have issue in rounding off for tax code.

Tax code field when I keep Normal in rounding form system take sales tax code calculation amount as it is i.e. Rs.100.70

When I select rounding - up system take Rs.101.

When I select downward system take Rs 100.

Actual I want nearest .

When my tax code amount Rs 100.70 it will take 101.

When my tax code amount Rs 100.30 it will take 100.

Help me.

Thanks.

Avinash Sathe.