Income tax computations inapropriate on decimals

Hi Guys i have a question on how does tax works on salary slips. In my scenario if the tax is rounded off it is OKAY and the amount is right… but im having confusion when it is not rounded off yet.

In my example i have an basic amount of 48,569.14 minus 20,833 multiple by .025 plus 2,500 and in my calculator it shows 6,309.035 but in erpnext system it shows 6,308.84 i know this is just a small difference and when i rounded it off in nearest one i will get the right rounded off amount my only concern right now is the amount when it is not yet rounded off. Hopefully someone can tell me why erpnext is computing different specially on decimals. Thanks in advance.