Why is the running total on Account Statements different depending on the Statements starting point?

A "Running Total" is not the same as a "Balance Total".

The Running Total column that is down the right hand side is reflecting the accumulative total for the information displayed up to that point. This number WILL be different if you start from a different point. However, the final total along the bottom should be the same once the PrePay Balance and Credit Advances, etc. are added into the detail's total.