I've had stalls well above 180*, depending on conditions. One thing to remember about handling meats is that once you remove to foil, etc. you reduce thermal absorption rates, and this can in turn prolong an existing stall, or simulate a stall. A true stall is a result of natural moisture in the meat evaporating to cause a cooling effect. The temp at which a stall hits can be effected by smoke chamber temp, temp stability, smoke chamber humidity, type and quantity of dry rub and wrapped/rested after rub application(?!?!?), among other factors.
I mention rub and prep process because salt can cause an early formation of bark, which can reduce evaporation of internal moisture from the meat, causing a higher temp stall to occur, as the moisture has been reduced enough for the meat temp to continue rising. A dry smoke chamber (low humidity) will also cause early bark formation giving the same result. With a dry smoke chamber you will notice much higher retained natural moisture in higher finished temp meats, but may also see very long stalls as a result of the whole process.
Hang in there...the stalls are where everything is really getting happy inside, so just let it happen.
Eric