Talking to myself here but just in case anyone in Australia ends up in the same boat with GST and they won't because thay all have partner configured systems, right?
We were using the VAT Tax Inclusive option and all our prices in the database were GST inclusive. I've now changed this back to Tax Exclusive and now all our prices in the database are GST exclusive. This is good for us as we quote ex GST prices. I was trying to modify the templates to show the ex GST amounts, when I should have changed the Sales Tax option and then set the column headers to indicate ex GST.
I'm not saying this is the correct way to implement GST in Australia. This method works for us because we're a wholesale company and all our products are priced ex GST with the total GST listed in the totals in the footer of the invoice.
The rounding problem I experienced brought this to light because I was trying to work in reverse. There is no receipt variable for the tax exclusive price as it cannot be calculated with two decimal precision from a GST inclusive price. Now I'm working forward with an ex Price and adding Sales Tax or GST.
For example, $5.00 incl GST working backwards gives 4.545454... ex GST. If you round this to $4.55, then the total GST for many items is incorrect as it is out by half a cent per item. RMS calculates the total GST correctly but you can't show the individual ex GST price of $4.55 as it is rounded before the calculations. 4.545454... * 100 = $454.55 but $4.55 * 100 = $455.00
Bottom line is if you want to show ex GST prices in the entries on your invoice, use the Tax Exclusive Sales Tax option and price your database ex GST.