In BoG it was stated that Beerus was using 70% of his power against the Super Saiyan God.
Then we saw Super Saipan Blue being weaker than Beerus (while technically, regardless if it is a 50x multiplier or not, it should have overpowered the GoD).
After many arcs, when Goku And Vegeta had grown hugely more powerful than before, we see perfected SSJB Vegeta losing to Beerus (manga only).
Recently, we also got to see SSBE Vegeta (post Yardratian training) losing to a weak Hakai from the God of Destruction.
I mean, isn’t Toriyama just increasing Beerus’ power every arc? We have been told that he used 70% of his power against SSG, but now he can even defeat an enraged, super-trained SSBE while playing around!
What could be the possible in-story reason for this (except for making the story more interesting, of course!)?