Trailmanor does the same thing. I've got a single 3500# Dexter axle under a trailer with 4230# GVWR. And, the posted GAWR is not 3500# but 3619#, since Trailmanor believes the weight of the wheels and tires do not count. It's all part of making an extreme light weight trailer.
Other companies are much more conservative. Keystone puts 4400# axles under some smaller Passports, Cougars and Laredos. The Northwood Mfg. and Outdoors RV puts 5200# axles under some of theirs. The Outdoors RV Timber Ridge 240RKS has two 5200# axles and GVWR of 8100#. THat's one reason why these trailers are considered more rugged than the light-weights.