Over a million most likely means just barely over it, anything bordering on 2 million would use that value as frame of reference.
And doesn’t the current scale have 2nd form at just 2x first form? Highly unlikely it’s powerlevel would be close to 1,500,000 then it’d be rated as much higher than just the 2x we give him.
But if we’re going to be really pedantic over not using Powerlevels alone and just as frames of reference, you could say that since pre Zenkai Namek Goku with a KKx6 would have a of PL = 540,000 practically equal to First Form Freezas 530,000 then he’d be around 80% stronger than that at KKx10 given the linearity of Kaioken and still only have a powerlevel of 900,000, well below 1% of FF Freezas power.