And again, you're assuming Goku thinks this is Beerus' full power. Goku probably just noticed that Beerus wasn't even trying and thought,"Wow. If this is him not even trying, I can't imagine him going Full Power and going all out." Heck, Goku even complained to Beerus during their fight that Beerus wasn't "showing his true strength", to which Beerus replied, "I'll only show to you what's necessary". Why would Goku then assume that Beerus used full power and effort into a single flick and shoulder touch? And since Goku can't even sense Beerus, how could he even make that assumption if he doesn't know if Beerus is 1,000,000x stronger than him or only 10x stronger just based on feats?Lord Beerus wrote: Because if Goku hypothetically thinks that Vegetto in any capacity wouldn't be enough to defeat Beerus, who was using less than 10% of his power for all intents and purposes at that time, and using the 1-15 scale for God tier characters, SSJ3 Vegetto being a 4.8 on your scale doesn't work at all. If SSJ2 Raging Vegeta can make Beerus use 10% of his power to tank everything he was throwing at him, what does that say about how much power Beerus was using when kicked SSJ3 Goku's ass? Especially when Beerus specifically makes the comment about how much more fun he had fighting SSJ2 Vegeta than he did fighting SSJ3 Goku. Goku came a solid conclusion, judging from his first encounter with Beerus, that fusing with Vegeta wouldn't enough to defeat Beerus. That is the be all and end all. Then after Beerus fights Vegeta, he make the statement that he had use 10% of his power to handle Raging SSJ2 Vegeta and then makes the comment that he had much more fun fighting Vegeta than he did Goku on King Kai's planet. This all heavy implies that Beerus used a quite a lot less power when he fought Goku originally. Perhaps around 3-6%. The same amount of power than Goku believed would able to defeat hypothetical Vegetto in any form.
So in reality, this is how things stand:
Beerus (10%) >> Enraged SSJ2 Vegeta > Beerus (<10%) >>>>> SSJ3 Vegetto >>>>> SSJ3 Goku
And going by the 1-15 for God tier characters in BOG/ROF/Super, SSJ3 Vegetto doesn't rank on the scale.
Heck, from what I listed, Rageta is stronger than regular SSJ Vegetto anyways, so even if Goku mistook Suppressed Beerus for full power, it would fit. There is, however, no implication that Goku was even factoring in hypothetical forms when he mentioned Fusion. He probably just factored in what he knew, which was SSJ Vegetto from ~5 years ago (though I still have beerus beating SSJ3 Vegetto).
