Mr. Popo can literally eat a Kamehameha in the anime, but respects the Oozaru Fist.
Goku's Kamehameha probably can't finish King Piccolo, yet Oozaru Fist punches a hole through him despite his blocking.
These are major, major feats, man. Just something to think about. I took a long time to really absorb this, but I find it to be more likely then not.
But again, Piccolo's word stated in the way it did, as DE confirmed, it's established in JP to be commonly associated to a 3~6x boost. So Piccolo Junior > Piccolo Daimao (young) is likely within the 3~ 6x range, possibly 5x like the boost Piccolo got with Nail with the same word used.
Besides, eating KMHMH was in the anime, and the way Popo addressed Goku can easily be taken as testing Goku's motivations considering Shen stated Yamcha might to take too much time to surpass him. It was likely a way to test Goku's resolve under difficult situations, and upon seeing Goku wasn't shaken by Popo's words, Kami stated he's help to hear that...
As I mentioned too, the Oozaru fist was never established as an on top 10x boost over the existing one. Goku may have gotten a 10x one upon recovering from the water, but still not quite, and the Oozaru fist being him assessing that power effectively... Even more so with, again, Kami deciding to keep the moon, an irrelevant thing as it seemed, up again, rather than having a 10x boost asset vs Piccolo Junior, while he wasn't that confident of Goku's win, as he said he left most of his training to Popo.
Sorry P, I won't buy that one as it isn't much supported and there are heavy things going against that.
@BedroomBully thanks man. Much appreciated. Gotta give P credits for this list a lot, it was after debating him many times, seeing his old debates with SSJ2 when I wasn't even apart of forums and with COH too, and seeing old his old lists ignoring scouters, as well as Kyo's, that I thought about this one, which is a reflect of the many debates P, SSJ2, COH, Kyo and the old crew had on DB which helped me to have a better clarity on a lot of things, I've never thought this all alone in the least.
They shaped the entire part 1 scaling. I mostly absorbed from them haha
Captain Cadaver and Kenshi too.