BTF is right...

If you did that well with your other plants then its most likely just the different strain.

They have cash crop strains that are bred to have huge weight and theres headstash strains that give much better meds. Personally every bud ive had that was fluffy and wispy were very good. I just recently chopped some automatics and one plant had a wispy fluffy pheno and was the best smoke of the 3 plants that were the same strain.

I didnt know that heat stress could also cause fluffy buds...interesting.