Treating a statement as trashtalking only because it makes the gaps too big for your taste is not the proper way to make the ultimate PL list you dream about.
Remember Vegeta expected the three new androids to be a lot stronger than Nineteen, yet he was confident he could defeat them even if they fought him all together. That implies a massive gap.
Nineteen << Expected Eighteen <<< Vegeta
Or maybe it's even bigger. Come to think of it, I don't think...
He was drained because the android had absorbed his energy, the same way Perfect Cell was tired after fighting Goku without using full power. And there are many cases in which one can tell how powerful a character is without using his full power.
In my books, Baba Saga Gohan is at 90% of Oozaru Goku. I don't see why he can't have improved a little in the afterlife, so maybe back then he was at 80% of Oozaru Goku.
-Nineteen and Twenty were originally written as the two Androids about whom Trunks said he could barely fight them evenly one on one. I don't think that power was ever retconned, since AT wrote their battles with that in mind.
-It is stated that SSJ Vegeta doesn't start out at full power against...