Edit Order Mods Tax problem

[avf]

Hi,
I have installed the Edit orders mod and have basically 2 tax classes at 4% and 12.5%.

When I click on the details button and then update the order. The order total is affected as now the 2 differnt tax amounts calculated at 4% and 12.5% for different items get added up and I basically get 2 tax amounts equal to 4+12.5=16.5% whereby making the order total incorrect. The pics below show the actual invoice and then the invoice after I update. Please help

Thanks in advance
neel