You believe SSj Goku was at 150,000,000 and 100% Freeza at 120,000,000, correct? I can tell you why that doesn't work, and why Freeza has to be much stronger. I will not hold back any information from this post. Any estimations I show will be backed up fully. I will provide manga scans, too.
150,000,000 / 120,000,000 = 1.25x difference.
It may not seem like it, but that is actually enough of a difference to be able to easily manhandle an opponent. I provide two examples:
Vegeta vs. Zarbon
Vegeta's power level was stated as 24,000. Zarbon's is estimated, usually, between 21,000 and 23,000. I am going to put him at 22,000. Why?


As you can see, Zarbon is not only talking like he's shocked Vegeta reached said amount of power (22,000 at the time), but like he's scared, too. One would think that he wouldn't have problems talking while saying this if Vegeta wasn't stronger than himself. But he's obviously not equal to Vegeta. Sound reasonable?
24,000 / 22,000 = 1.09090909x difference. What does this specific difference mean in a fight? Well...
Vegeta fought with a smile on his face nearly the entire battle only showing signs of difficulty when he knocked away Zarbon's blast and when he threw him through the air. Not receiving a blow in battle but leaving your enemy bruised and bloody. Not "breaking a sweat". In other words, you own the entire fight even though you're only roughly 9% stronger than your opponent. If you wanted me to I could scan all 9 pages of their fight.
The other fight is Vegeta vs. Kiwi.
Vegeta (24,000) vs. Kiwi ("barely 18,000").
How do we know how strong Kiwi is?

How do we know how strong Vegeta previously was?

24,000 / 18,000 = 1.33333333x difference. Enough to kill your opponent with a single attack, because that's what Vegeta did.
Get what I mean? Logically Freeza would have to be stronger to even want to think about fighting with Goku. Heck, near the end of their battle when Freeza's ki finally begins to burn out, that doesn't even seem like a 1.09090909x difference as Goku and Freeza are practically blow for blow, but Freeza's slowing down. So, it should be anywhere from 1.01x - 1.07x/1.08x difference.
Goku shouldn't be any weaker because it would take more than 40x his base strength (before being weakened) to take Freeza at 100% full power.
150,000,000 / 1.01 = 148,514,851
150,000,000 / 1.08 = 138 888 889
Freeza would have to be somewhere in that range of power.






