When you smoke weed you are smoking the plant and all of its various terpenes, cannabiniods, etc. This causes a tolerance to all of the plant constituents, when you smoke wax you are smoking mostly THC so you only get a tolerance to that one chemical component of the plant. Although the cannabiniods have cross tolerances they probably aren't 100% cross tolerant which would perhaps make someone who almost exclusively smokes wax more sensitive to the whole plant.
Weed tolerance is strange, for the first 3 years of smoking I never gained a noticeable tolerance even though I smoked frequently. I could get really ripped off of like ~50mg of good bud. I took a break for a couple years due to mental health issues and when I came back to weed my tolerance had at least tripled even though I hadn't touched it for years.