Accumulated value rollover

I have an indicator that is collected from an online data source.  The indicator is collected on a polling schedule every 6 hours.

It is measured as an accumulated value and has a roll-over value of 1,000,000.

When the online source (PLC) is turned off for maintenance, a 0 can be recorded for the current value causing the accumulated value to rollover.

Once the PLC is turned back on, the counts are read but with the addition of 1,000,000 counts.

Any suggestions on how to correct this issue? 

FYI.. this is APM V7.8.

Thanks for any ideas.