Problem in Excise Condition % in PO

Hi,

In development server I have created one normal PO with 2 materials for both the materials the chapter ID is same and from 27.02.2010 the excise % is maitain as 10% but when I creat PO for one material system have taken proper Excise % as 10 % but for second Material system has taken % as 16 % even the chapter ID is same for both.

what can b the problem.

regards,

zafar