it is bs because it's just fans trying to justify why such and such is stronger than such and such....the canon created by toryiama didnt separate the levels into all those sub groups, it was fans...that's what i'm trying to tell you...he had 3 original levels: ss1, ss2, ss3....now, could the charaters get stronger inbetween levels? yes, but they were still considered whatever ss level....ex: gohan was obviously stronger before he went ss2 against cell, but he was still considered a ss1 until he made the complete transformaton...
They still explain the difference though, when they were ssj1. Vegeta and Trunks were trying to force another transformation before fully mastering ssj1, which Goku and Gohan did. They did that by staying in that ssj1 form all the time, to the point where it was no big deal to turn ssj because it became so normal for them. So that's still a different level than what Vegeta and Trunks did, with the whole pumped up and losing speed (Trunks) transformation. Goku tried that form and said
this aint the route to go and went a different route. So it's more than who's stronger than who, because if Trunks hadn't lost so much speed, he had the strength to fukk with Perfect Cell.

At the begining of the series Vegeta is WAY stronger than Goku, they had to spend an entire year training for Vegeta and Nappa, and they still weren't strong enough to beat him in a fair one. And yes both Vegeta and Trunks were training their whole life, how else did Trunks learn how to fight and become a ssj as a teenager?
and showed him he was too slow. Don't tell me to read nikka, I know this shyt