Chapter 341 (DBZ 147), P8.4-5, P9.
Piccolo: “Have you noticed too, Gohan?...”
Gohan: “Y-yes…”
Piccolo: “Son Goku is rushing the match for some reason…He’s already putting out close to his full power…But even so, what’s with that miserable condition of his?...”
Tenshinhan: “Th-that miserable condition…!? What are you talking about? Goku’s overwhelmingly pushing him back…!”
Piccolo: “It’s not that. As a Super Saiyan, Goku’s power should be more stupendous than this…”
Note: Several people thought this quote was contradictory, due to how Piccolo says Goku is using almost his full power but should have much better power than that. To me though it seems pretty straightforward: Goku is using almost all the power he has in his current sick condition, but Piccolo realizes Goku's full power should be much more than that.
This example even uses the same terminology in Viz. Piccolo calling Goku's condition miserable along with saying his power should be "more stupendous" isn't too dissimilar to saying he should be much, much stronger. Yeah, it might not be the exact same thing, but the point being you don't need to be multiple/hundreds of times weaker than your full power to be significantly below where you should be.