GST Producing incorrect values

Hi,

We are experiencing an issue in our business where the GST(VAT) is not calculating correctly.

The amount before GST(VAT) is $558.13 and the GST calculates to $55.83 instead of $55.81
It should round down to the $55.81 but even if it rounded up should go to $55.82.

Any ideas as to where I should start looking for this.
Has anyone else come accross this issue before?

I have attached images so that our products on the invoice can be seen.

Thanks in advance.