Except he is later stated to have gotten stronger, so we know. Goku didn't come out of the healing chamber and say "I'm full power now", he was marveling at his own strength. In the incident after eating the fish, there is nothing stating he got stronger.withheldforprivacy said:Vegeta said he'd use the healing booth to get Goku ''back to full power''. I guess that means Goku remained at 90.000
Vegeta also said that Goku wouldn't have gained any power from healing because he was a low-class Saiyan.withheldforprivacy said:Vegeta said he'd use the healing booth to get Goku ''back to full power''. I guess that means Goku remained at 90.000