Yes they need sufficient heat for digestion, and folk will vary in their methods. I keep animals below the extreme max of their thermal range. The hotter the reptile is kept, the faster its metabolism. While it needs to be hot enough, being hotter than nessesary is not nessesarily a good thing, even when they seem to like it.
Higher than average temps for the species, boosts the metabolism, increases appetite, often leading to overfeeding and a growth rate way above the norm, which cant be good for skeletal development, and if really hot, a shorter life due metabolic burnout. If your lizard develops an internal infection, its increased metabolism will accelerate the rate of infection, since you wont know till symptoms are apparent, by the time symptoms show, its infection will be severe, more so than a lizard kept at lower temps. On the flip side, sometimes an increase in temp can assist recovery and is often done with lizards suffering respitory infection.
If you ask me, warm enough to digest and hunt, is warm enough.
If you ask ten people the same question, you'll get either ten different answers or ten variations. *shrugs*
My two cents worth comes from years of pers obs, but like all advice, its free!
Incidently Juli their natural habitat is a big range. Variations in temperature from inland to coast make them quite tolerant of variation in captivity. Just because they tolerate a varience and appear to do well, dosent mean a particular temp must be ideal,
my own included, simply that they are tough lizards!
Best wishes
