Private Ryan said:
Using your full power in an injured state =/= being at 100% power. At best, Freeza's injuries were superficial, because after recovering from the Genki Dama, Freeza is not shown mentioning his injuries to Goku or mentioning them to himself at all.
Sorry, but that's not the case. The first thing Feezer says after the Genkidama is that Goku nearly killed him with it. The second thing he says is that despite being hurt (or badly hurt, depending on the translation you use) he can still kill them all.
Furthermore, Goku knew the extent of Freezer's power and even that he wasn't fighting at full strength, so it doesn't make much sense that he would miscalculate the strength of the Genkidama (he intended to kill Freezer with it) to the point of only doing "superficial damage" to him.
Private Ryan said:
The second quote is in reference to how Freeza's ki continually falls at full power, because his body is unable to handle it. It doesn't have anything to do with any past injuries.
Chapter: 321 (DBZ 127), P5.2
Context: Freeza’s still powering up
Freeza: “85%...90…”
Goku: “Freeza…The reason I’m waiting for you to reach full power…is because I want to beat you down when you’re at your best…That way, you’ll have no regrets as a warrior…You want to try testing out your full power too, right? If you didn’t, you would have just fired at the planet again and ended it…”
Note: Goku might be talking about himself, or both he and Freeza, not having any regrets as warriors.
The whole reason why Freeza was powering up to his full power, rather than obliterating the planet, is because he wanted an opportunity to test his full power. This meaning is completely lost if his full power actually turned out to only be ~20% of his power.
But loosing Ki because of the injuries is a basic rule in DB. Freezer had never trained once in his life (it was explicitly said in FnF, but it was apparent here when he confessed that he had never used his maximum power) and that translated into a body that couldn't properly resist fighting at maximum power.
So Freezer had that handicap added to the general rule of losing power with the injuries. In other words, unlike most other fighters in DB, Freezer loosed strength when fighting at his 100% even if he wasn't injured, but that obviously doesn't mean he didn't also lose energy when he was injured. In fact, we have pretty blatant evidences of that, for example, how after being cut in half by its kienzans he lost all his energy to the point of not being able even to fly.
Finally, when Goku says he will wait until Freezer reaches his 100% he isn't speaking about its injuries. Injuries are part of the fight and he was injuried as well (he regained his power thanks to the rage boost, but that's also part of the fight). And Freezer wanted to test himself fighting at his maximum power. But not test in the sense of "what can I destroy now compared to then" but in the sense of "I'll fight until I reach my own limits".
Private Ryan said:
Chapter: 325 (DBZ 131), P8.2-5
Context: after Goku and full-power Freeza have fought for a while
Goku: “I quit. [ ] As a backlash from you using your 100% power, you’ve passed your peak, and your ki is steadily dropping…I’m starting to think that there’s no point in fighting any more than this…”
If Freeza wasn't able to use anywhere near his full power, then obviously he didn't pass his peak.
His peak in relative terms, because that's what caused Freezer's body to lose his strength. It doesn't matter if that 100% was weaker than the previous 50%, because in terms of forcing the body and fighting to the limits, 100% is still 100% and the peak Freezer could reach (at that moment).
Private Ryan said:
Chapter: 325 (DBZ 131), P9.1
Context: Goku continues to explains why he doesn’t feel like fighting Freeza anymore
Goku: “I’m already satisfied. Your pride is in tatters…Someone has appeared who surpasses you, Freeza, who supposedly no one in this world could surpass…And this person was merely a Saiyan…”
Once again, the whole point of Goku saying this is completely moot if Freeza wasn't actually using his full power. The idea is that the legendary Super Saiyan arose up, the one person that Freeza feared. This is absolutely nonsense if Freeza's true full power would wreck SSj Goku. It makes the entire theme of the Freeza Saga moot. Not to mention, Freeza is never shown resenting any injuries he has from the Genki Dama when fighting Goku, which shows that they weren't a hindrance to him anymore. SSj Goku was simply stronger than Full Power Freeza.
That would be true if Goku had been talking to the readers instead of talking to Freezer the character, but that wasn't the case in DB.
Goku hated Freezer and despite respecting him as a fighter he wanted to hurt him as much as he could (pride included), so it wouldn't make any sense for Goku to explain to Freezer that he won because he got him with the Genkidama.
That's like saying that Goku had more than 120.000 units when he arrived at Namek only because he didn't explain to Ginew that he reached 180.000 units of power thanks to a special technique called Kaioh Ken. In fact, not only Goku doesn't tell Ginew anything about the KK, he even implies that the 180.000 wasn't his full power, even when in reality that was already double his full power.
But the fact that Freezer had been badly injured and still managed to match SSJ Goku's strength, some factual data from the Cell saga and Toriama's interview all confirm that Freezer was much, much stronger than Goku SSJ.
Fearless Boo said:
In the super exciting guide.
http://i1110.photobucket.com/albums/h441/Fox_969/toriyamassj.png
"To be honest, the way I decided upon the Super Saiyan design was for such a... simple reason that it’d make you go "eh?". I only use one assistant (note 3), who has always helped me. My assistant always had to spend a lot of time blacking in Goku's hair (note 4), so the biggest reason was to save time, since if Goku became a Super Saiyan, his hair wouldn't have to be blacked in. What's more, this also had the effect that one could tell with a glance that Goku had gotten stronger, so it was killing two birds with one stone.
At the time, it was made out that he was fifty times as strong when he became Super Saiyan, but that's a little extravagant. As far as my feelings as an author go, I think I drew it with the sense of it being a change of about ten times what he had been up until then."
But that's obvious. Nothing in the manga points to Goku SSJ being a 50x over his base state (in Namek at least). He barely matched a badly injured Freezer while 50x would have been a 1-hit kill to a 100% non-injured Freezer. And that 10x multiplier is further confirmed in the Cell saga through some evidences that Toriyama put in there.
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