Most all care sheets for ball pythons I've read (and I've read a lot) show the ideal basking temp to be 88-94 degrees. That makes yours seem a bit low. Considering that heat is used for digestion, it may help with that lump in your snake getting processed to its fullest. I'd recommend upping the thermostat to 90 degrees for the warm side. At night, most snakes seek out a warm burrow or rock that can hold in the heat from the day. I noticed that before I had a UTH, my snake would come out and sit on top of its hide at night because the hide (made of rock) was warmer on the outside than inside.
You seem a bit defensive about your temps, but there are a lot of people on here who are experts with snakes and they have good advice (I'm not an expert, but I try to only state things I know are true).