The lower temps are just a little to low for me, I would rather see the snake's body temps not get below 80 degrees, and ideally stay between 80 and 90 degrees. One thing that most of us forget in the big scheme of things is what is the snake's temp, the best way to measure this is with a temp gun, in my opinion having a temp gun is imperative for measuring the snake's body temperature. If the ideal temp to incubate the eggs is 89 degrees then this must also be the same ideal temp for the adults. The eggs are usually laid underground in termite mounds and rodent holes where the adults also live.
It is more likely for a ball python to get a respiratory infection if the temps are too low, during the lower temps our snakes become stressed. If the snake is in stress it's normal ability to fight off infections is impaired, In my opinion warmth (80 to 90 degrees) is more important than food. If you are only working with one heat source I would double that. Ideally snakes kept in a terrarium in the home should have a under tank heater and an over the tank heater inferred, ceramic or heat pad all heat sources should work from a thermostat and all probes should be making intimate contact with the heat source.
If you think the snake has RI a trip to your local vet might be the best way to go.
If you have any questions feel free to contact me my phone # is 408-981-6694 and my email address is fgsnakes@sbcglobal.net
Good luck
Brian / For Goodness Snakes