Magento

Since the upgrade to 1.4.1 I have noticed changes to the reported daily balance..never on the same but a few days later. For instance I will have a daily sales total showing of $1169 on a given day. Two days later that amount is showing $863 for the daily balance. What can be causing this issue? I am showing less revenues than I am depositing onto my bank account and this is becoming an accounting nightare.
Any Ideas?