Right, i agree that 222 is not TOO warm, but is IS warmer than the stock system is designed to run. Granted you don't have a "stock" system but i don't see any reason why it would be running warmer than designed.
WRXSD, IAT of 180+ degrees in hot traffic is completely normal for a heatsoaked engine. I don't see how this would have any impact on your thermostat. OP already has a mishimoto radiator, IE all aluminum. A completely stock cooling system should have no issue dealing with ambient temps up past 115F under normal load. I have done plenty of AC- on driving in these temps with no issue...until my thermostat failed eventually, but not related to temperature i don't believe.
If either of you have a protune, check your AC ON idle speed. It should be ~1100 rpm IIRC.