SIAD said:
Yes, but Gohan was a possible witness to the power of Vegeta SSJ2 (Enraged), who beat Bills (Ultra deleted), which in turn was declared by Goku that not a hypothetical Vegetto SSJ3 (BoG) could against. Therefore: SSJ Goku (Powers Combined)> Vegeta SSJ2 (Enraged)> Bills (Ultra deleted) >> Vegetto SSJ3 (BoG) >>> Vegetto SSJ3 (Boo). If it were a simple sum of powers, probably SSJ Goku (Combined Powers) did not even have the same power that Goku SSJ2 (BoG).
 We can also see that Krillin was 100% witnessed the power of Vegetta SSJ2 (Enraged) and still, thought that Goku SSJ (combined energies) had become SSJG, but Piccolo as best judge realized that the power of SSJ Goku (Powers Combined) was not up to Bills, as witnessed that Bills to turn against Vegeta, showed that it was much more powerful and even Wiss had recently stated that Bills could destroy the Solar System in an instant. I see something like this:
 Goku SSJG (100%) >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SSJ Goku (combined energies) > Vegeta SSJ2 (Enraged)> Bills (Ultra deleted) >> Vegetto SSJ3 (BoG).
 If it had been a simple sum of powers, Krillin had not been a "silly to the extreme" for calling Goku SSJG just to have the combined energies.
Goku was estimating Beerus 100%. By the movement of Beerus, he can tell that Vegit won't be enough to stop him.
Beerus [Goku estimation 100%] >>> SSJ3 Vegito BoG
Now Beerus against Z Shenshi is the same one against Goku. Vegeta enraged did better than everyone and he made Beerus bleed which nobody else did it before which implied that Vegeta is the strongest at that time.
After the fight. Beerus said that Vegeta is not the SSG either which implied that he was letting Vegeta to hit him.
Beerus [Goku estimation 100%] >>> SSJ3 Vegito BoG >>>>>>>>>> Supressed Beerus > SSJ2 rage Vegeta > SSJ3 Goku
After Goku absorbed everyone's power. Gohan stated that Goku is the strongest in the history which should include Vegeta too since he contribute his power as well. Keep in mind that Vegito shouldn't be include here since Gohan was absorbed at that time when Vegito existed.
Beerus [100% by Goku] >>> SSJ3 Vegito BoG >>>>>> Supressed Beerus > All power absorbed Goku > SSJ2 Rage Vegeta
Goku stated that SSG power is completely different dimension and will never achieve it by himself and thought that he's enough to beat Beerus which imply that he has a better chance than Vegito at 80%.
Beerus [100% by Goku] ~ SSG Goku 80% >>> SSJ3 Vegito >>>> Supressed Beerus > Goku all power absorbed > Rage Vegeta
Now Beerus said he was just using 70% of his power and never power up except he increased his speed.
Beerus 70% >= Beerus 100% by Goku ~ SSG Goku 80% >>> SSJ3 Vegito >>>> Supressed Beerus > Goku all power absorbed > rage Vegeta