There's probably enough of an air gap between several sheets of paper towel that the temperature could drop on the top paper towel UNTIL something heavy - like your ball python - lies on them and they get compressed against the bottom of the glass.
Also, OP has said he's not using a digital thermometer or temp gun so he really doesn't know the surface temperature on that top paper towel.
If you read the entire post, I m using a digital thermometer but it doesn't work and I need to get a new one. It was fine for the first few days, but then started getting all jumpy and weird so I have to return it and get a different one.