When you signup with us, you agreed with our terms and condition; which clearly states that "we are not responsible for client end billing. We are only responsible for our end billing." So, we are not going to check as per your billing system records.
We always do 4 Digit roundup with rounding method as UP, so you may get difference if you are not doing 4 digit roundup at your end.
you should be having clear knowledge of billing rounding, we are not responsible to teach you about billing roundups we assume you are already having knowledge of carrier grade billing , if you are raising any dispute without getting aware of rounding we are not going to entertain your dispute and we will dismiss the dispute. Round digit and method is clearly mentioned in portal under Interconnection Page.