From what I've read yeah it's quite important to have a good humidity.
Maybe your humidity gauge is not working right, if you're misting twice a day then the humidity should be more than that so I would check your gauge first
Only had ours for a few months but you definitely don't need a basking light I'm not surprised your humidity is so low.
Do you Mist it twice a day?
On ours we have a 12w heat mat on for 6 hours in the day and then when that goes off put the blue 15w incandescent bulb on which gives off heat...