Implement new tax rate on Invoice

Hi,

We have requirement to running new tax rate. we already setup and do some test on test environment. as far as we know that the tax are assign on supplier site level as we use on both environment and production test. we already do some test with condition below :

1. Create new invoice without PO and use new site with new tax rate and the result as expected.

2. Create new invoice from existing PO that use old site with old tax rate and on invoice we use new site with new tax rate and the result is the tax rate on invoice still use old rate (po tax rate) after click calculate tax. Then we change the tax rate manual on Tax Details then click calculate tax again and the result as expected.