Tax Is Not Calculating Correctly

[bitznbytes]

My TAX does not seem to be calculating correctly:

 

When I reach the checkout_confiramtion.php page the tax is always rounding up or down depending on what it is closer to. Ex: if the tax is $5.04 it rounds it down to $5.00 and if it is 13.88 then it rounds it to 14.00 - has anyone seen this before? Do I have something not setup correctly?

 

Thanks again,

B