I am asking for this patent. It should be 2023, right ? Or am I missing something ?
US patent system has a provision under USC 154 which awards days equal to amount of days that patent application has spent in the prosecution at USPTO after the statutory limit of three years.
The patent has a PTA of 1854 under USC 154 (b). Which is to be added to the actual expiry.
As RishiM_IPR states, if the patent prosecution takes over three years, there can be patent term adjustments. To verify this, go to the US Public Pair site, select "Patent Number" and enter "7792728" (without quotes). Once it loads you'll see a tab labeled "Patent Term Adjustments". For this patent, there were "Non-Overlapping USPTO Delays" of 1890 days of which 36 days were considered "Applicant Delays" which don't get adjusted for. The result is 1854 "Total PTA Adjustments".