Board Thread:Versus Battles/@comment-33029670-20190126214250/@comment-31165326-20190126221420

They went from 8-A to 7-B within a few hours

To say, they get roughly 202.750029409 Times stronger per minute

of course, there's probably fluctiations with how fast it is, considering Mettaton EX and NEO were able to fight Betty for a bit of time before they were overwhelmed, but it's still rather fast.