Alright, I gave this topic some thought and I wanted to talk about it for a bit and hear what you all have to say about it.
To cut to the chase, I think that Full Power (green form) Bojacks max power should scale above Perfect Cells max power (just perfect Cell, not SPC or even Grade 3).
The idea is pretty straightforward:
PC's max power Kamehameha was overpowered by SSJ2 Gohan's casual no charge Kamehameha (Gohan literally just says the chant and then quickly fires the blast with seemingly no charge up) and messes him greatly.
On the other hand, Full Power Bojacks max power blast clashes with SSJ2 Gohan's casual charged up Kamehameha (Gohan does the classic pose and we see the energy charge up) and they both explode on impact, which likely implies a relatively similar energy output cause if one blast was significantly stronger than the other, it would've bull dozed right through like against Cell.
So it would go FP Bojack Max power blast ~ SSJ2 Gohan's casual charged up Kamehameha > SSJ2 Gohan's casual no charge Kamehameha > PC full power Kamehameha. Note that I'm not trying to scale Bojack to SSJ2 Gohan (since he dealt with him rather easily), just that I'm using Gohan as the mediator to judge Cell and Bojacks performance.
Now for what people might have against this:
1. Gohan killed Bojack so easily compared to Cell, how could he be above him?
Gohan during his fight with Cell was purposely drawing out the fight so as to make Cell suffer, and it was only when Cell came back with a zenkai that Gohan decided to actually try and kill him (and by then the gap between them was shortened and Gohan was heavily damaged). He could've instantly kill Cell at anytime if he wanted to, but chose not too.
With Bojack on the other hand, Gohan had no such bloodlust and just simply wanted to take him down (which we see with him casually killing him in like a couple minutes). And Cell has Regen unlike Bojack, which benefits his survival compared to Bojack.
2. Gohan's Kamehameha was bigger against Cell than it was against Bojack, so shouldn't it be stronger?
While bigger beams do tend to be stronger, that's not always the case. KKx4 Goku's beam was bigger than the Kamehameha used against Bojack, but obviously it's not stronger. While the possibility does exist, the context surrounding makes me think otherwise: Gohan decided to charge up the attack against Bojack unlike against Cell which implies more effort, and Gohan is trying to kill Bojack while he's just trying to make Cell suffer.
To reiterate, I'm just arguing that FP Bojacks max power should be above Perfect Cells max power, not Grade 3 Cell or Super Perfect Cell/Post Zenkai Perfect Cell, just normal Perfect Cell. And I'm not scaling to Gohan, just using him as a middle ground.
Now if the Daizenshuu's or the movie claim that Perfect Cell (explicitly normal Perfect, not SPC or a vague "Cell is stronger statement") > Bojack, then forget what I posted. But if not, then please let me know what you all think.