I don't know the answer to your question I'm afraid, but what weight is Scooter. He does look smaller than most dwarf lops I've seen. I think dwarf lop starts from 2.2kg, but thy can be a good bit bigger than that. Maybe one of his parents was a smaller breed type.
maybe ask your vets, he was neutered today wasn;t he? they may have weighed him before the operation, how old is he, i he isn;t 6months he'll have some illing out to do yet :wave:
If Scooter was the runt of the litter he will probably always be quite small. I've heard that sometimes the small one from a litter remains significantly smaller, even when fully grown. I don't weigh my bun either to be honest. Quite a few Forum members have dwarf lops so hopefully one of them will come along soon.