Single post in Family exp bonus for Paradox Pokemon

Apologies if this has been suggested before, but I thought it was a bit strange that paradox Pokemon do not provide a party bonus for Pokemon of the same family. For example, my Larvesta eggs don't receive any additional exp when I have my Slither Wing in my party. I could see this being intentional since they aren't technically the same Pokemon, but I feel like it should work similar to Mega Evolution, and my Slither Wing came from a Larvesta egg so it makes sense for a Slither Wing to provide the same bonus that a Volcarona or Larvesta in the party would.