If you search through this thread for the terms "known issues" you will find a post I put together of all the known issues with Edit Orders and taxes..

Hopefully this will help you..

Quote Originally Posted by corrosie View Post
In my store I use two differente tax-rates....
After editing orders, the tax-totals are not correct.

When adding a product with a tax-type which didn't exist in the order before, the new tax-type is not shown at all.

When editing other orders (with both tax-types) the tax totals for both rates are the same. (the total of both taxes, instead of split up for each rate)

When I look at the code, is see that there is just one runnintax variable.

$RunningTax +=

Is there somebody with the same problem. And maybe already solved?

I am using v3.03 with Zen Cart 1.3.9h