It's invariably always a split CPID. In this case ABC@Home has exported stats and has a different CPID for you.
http://stats6.free-dc.org/user/wup/s...891e7b6d239aed
If you use the search function at top, it shows all your different combined accounts, this one shows that it gained 4M+ yesterday, offset that with your totals from yesterday on your main account and it gives the discrepancy.