Actually the way I came up with the above number was from adjusting the numbers manually
I am kind of worried about one thing when it comes to using your formula, what happens if you keep applying that formula to a number, like say change the frequency of 2 to 50%, then 70%, then 80%. All the changes to others will eventually result in a negative number.
Maybe that's the right way to go, just ignore those that are 0% or less since it all adds up to 100% right?