Excessive data usage by cox meter unexplained

Since half of May I see excessive data usage reporting by the Cox Orange County data usage meter.  Since June 1 I am measuring DPI (deep package inspection) on the Unifi USG router. So far, I measure 41 GBytes on the router, Cox measured 286 GBytes.  Yes, almost a factor of 7 difference.  I was out of town for 5 days, and each of these days Cox measured between 24 and 27 GBytes of usage.  At this rate 75% of my 1TB allocation will be allocated to usage I do not measure and which Cox is unwilling to verify. 

Since the discrepancy started half of May, after a planned cox outage, I suspect a programming issue.  Or perhaps they updated the meter. But my request for COX DPI or looking into it further, has been denied so far.  That is, unless I buy a total care package.  Really?  They claim my hardware is at fault, or I have too many devices, that somehow my wifi devices are not measured, etc.  Even though all my devices are measured and show up in my data reports.  After all, all data goes through the router.  None of them show a 25GBytes per day usage.

Does anyone else have this issue?