RMA Credit not wrong tax amounts

Hi All,

We have an issue with RMA credit memo tax amount are not calculating correctly, as this RMA is created for price correction for the source sales orders,

Source Sales order eg Qty - 20 Price 77.82 = total will be 1556.4

and there are some charges assigned at item level, when ever we create an SO these lines and charges also will be added, (Environment fee) charges and in AR we can see them as a separate lines there is no issue with this. when the RMA is created for price corrections in OM we can see as -10 * 0.8 = 0.8 is the price correction amount, and in AR invoices we can see the lines as