Inconsistent rounding of GST?

[#1]

Hello,

We have noticed of values being inconsistantly rounded when attempting to calculate gst where the tax will equal a value of xx.x55 (to three decimal places), which should get rounded up by a cent. Calculations were performed on https://www.moneysmart.gov.au/tools-and-resources/calculators-and-apps/gst-calculator by inserting the Ex GST Value.

Rounding:

Ex GST Value: 4.55

Tax (not rounded): 0.455

Tax (rounded): 0.456

Normal Inc Value: 5.01

Moneysmart Inc Value: 5.00

Not Rounding:

Ex GST Value: 14.55

Tax (not rounded): 1.455

Tax (rounded): 1.46

Normal Inc Value: 16.01

Moneysmart Inc Value: 16.01

There are plenty of other examples (e.g 17.55, 34.55 etc). Can someone explain the logic or rule that triggers the rounding so we can replicate it in our systems?

[#2 · Accepted solution]

As long as you are consistent, then I doubt it would make any real difference.

Just follow the same rounding rules for GST paid and GST received.