@ohgodwhy: Are you multiplying off of the last official power levels or just making a speculation using power levels. I'm asking because shouldn't Gogeta be able to destroy the Solar System like Cell was stated to be able to do?
I made up a little a maths formula on page 2, you can check it out if you like. It might not be entirely accurate but I was trying to take into account the minimum power required to take out planet Earth which I think I worked out to be about 9800. Then from that point on I just scaled upwards given the official power levels provided and in DBZ power levels are increased in a linear amount so it kind of makes sense. I came to the conclusion that Cell could probably have taken out a couple of planets with one blast, but didn't have anywhere near the power to live up to his claim.
I've heard the each transformation provided a x2 power up from the one before. This is also what's stated on DB wiki. SS3 Goku would have a power level of 600,000,000 at his very base form, obviously he was a lot stronger than this given his training. So if you think about it like that, Gogeta may not be x10 stronger but he definitely was at least twice as strong which is still massive nonetheless.