Greetings Kevin,
George brings up a great point, younger technicians sometimes fail to consider that dip switch setting on the primary air conditioner.
Here are some other considerations when dealing with roof air conditioners in extremely hot weather. Older units draw about 13 amps of current at 80 degrees outside. Every 10 degrees above 80 draws an additional 1.5 amps of current. When you get past 116 degrees you're dancing on the edge. Factor in dirty condensers and worn compressors and most older air conditioners will trip a 20amp circuit breaker.
When Cindy and I were living in our coach last summer in Tucson, AZ while our house was being built, I hooked up a misting system in front of my basement air conditioner condenser inlet and got the inside temperature down to 78 degrees when it was 112 degrees outside. The down side is it is kind of messy.
hope this helps, Fred