SIAD said:
Apparently there are 2 options, Shin and Goku could not see well the true power of Beerus in the Exhibition Tournament due to the dust that was there. Or maybe Beerus secretly started training after the ToP to keep up with Goku. Something similar to what Master Roshi did.
I'm starting to think that you're right about Beerus training. Though I'm having trouble figuring out the God of Destruction exhibition match. We see Beerus heavily damaged by the end of it implying that he isn't leaps and bounds above the other gods. However, prior to the match we see CSSJB Vegeta vs Beerus, and Beerus states that Vegeta could become a GoD in another universe despite being so far behind himself.
Ch. 27, pg. 34.2-5
Context: Beerus defeats Vegeta with ease after getting serious
Beerus: “You got carried away while I was going easy on you…”
Vegeta: “Gah… Dammit…”
Beerus: “At this rate, it’ll take a million years to become my rival! Well…I’ll give you points for improving so quickly. You could probably be a candidate for a God of Destruction in another universe…”
So which is it? Are the other gods closer to Vegeta's level or are they close to Beerus?
What I would point out is that Beerus' incomplete UI was shown to be able to handle all of the GoDs simultaneously, so perhaps he starting working on his UI after the ToP.