Import while specifying Tax amount

I tried searching the asked questions already and didn't find someone asking the same question.

I have a couple payments from an eftpos provider almost daily, and it's a pain in the butt entering them manually into MYOB as a receive money transaction split into 4 lines.

Ideally I'd like to be able to use an import template to be able to make it quicker because then I'd be able to do multiple days in the same upload.

The issue here is that the provider is quite often out with GST by about a cent, which means that if I upload with just GST flagged, the GST that MYOB calculates will be incorrect, and I'd like to avoid having to go to each day and manually adjusting the GST amount - especially as we are expecting to be having more of these eftpos terminals come online!

Is there a way to have GST flagged in the import journal, while specifying the amount the GST should be?

I tried a few ways and it always said the import was unbalanced. Any help would be greatly appreciated!