Yeah, taking that at face value true, it would suggest that what Cell took from Goku then, the KMHMH amplification, was nothing compared to what current versions of Goku could put forth in amping his KMHMH.
Tbh, when I was younger and read that for the first time (as well as watched the anime) I thought Piccolo was referring to the power the KMHMH had being exactly the power Goku had from that time, that is, maybe 32,000 vs Vegeta. While that's a straightforward interpretation and may be even what Toriyama had in mind for all we know, it would go without saying that Cell, a SSJ level threat, wouldn't use a 32,000 attack.
It's also weird when factoring the KMHMH as >> 2.22x to me since Piccolo says that was nothing to worry about and, later on, calls the KMHMH pathetic... If it were a 2.22x amp right then, then that would be an attack surpassing Full Power Piccolo, #17, maybe, depending on one's gaps, rivaling #16. It'd be like Saiyans saga Vegeta calling a 30,000 chi blast a "pathetic attack". Or if Goku could put forth a, let's say, 1,800 KMHMH, that being called pathetic by Raditz. It wouldn't be pathetic at all since if it hit home they'd be pulverized. It'd basically imply that a KMHMH that is wayy beyond Piccolo (since a 2.22x gap would put that Cell far above Piccolo) is pathetic because it could be even stronger... I don't agree with that, if it's so beyond him that it has the potential to completely wreck him, then it shouldn't matter whether it was 2.22x or if it would have been, like, 3x now... Because the threat had it hit Piccolo would be the same.
Which is why I don't like to think in chi amplifier attacks logic. I don't think the 2.22x one was being factored in fully after a certain point. Even when Kaioken x20 Goku could already be somewhat close to 50% Freeza (like what, like a 60 vs 70 gap?), Freeza could still stop it without powering up to even 70% of his power... While if it followed from 2.22x plus, it could make the KMHMH itself already on par with 100% Freeza.
So I think that either the 2.22x was only valid in the Raditz battle and not anymore, or Goku and Piccolo were actually way stronger there when fighting, like in the ~800 range and then, the KMHMH and the Makankosappo wouldn't carry all that huge amplification over their read powers before fighting (being more like 1.2x and 1.7x amps respectively), which would work better power level wise and the potential a 2x power up entailed in the Cell arc. Let's say Goku evolved from 1.2x to 1.5x with the KMHMH... And 1.2x was not anything to worry about for Kamiccolo, but a 1.5x would have been a thing already to be cautious of, the now Goku's amplified attack, were it to hit home ofc.