Wordtracker and mister Dan Richmont from the Seo in Practice and developer of the program uses a different formula.

I believe that you should be able to adjust the formula yourself.
For example in less competitive markets it is easier to rank high and therefor you could use for example number of searches times three instead of times two to get a higher KEI.

I believe that with times square the fluctuations of KEI numbers are to high.

Any thoughts on this matter?

While I personally would not have a problem with that, I can only imagine the mess some users would make for themselves, and cause a deluge of complaints about how the software sucks and so on...

Keeping it standard for the time being makes the most sense, as lets be honest KEI numbers mean absolutely nothing and neither do the competing pages alone. That is a very unhelpful and rather simplistic metric.

Its only one very small piece of a larger puzzle, which includes back link profiles, domain authority, etc, etc, etc.....

I use KEI all the time to help me make a good judgement for which keywords I can get the best results with. For this reason I think it is very useful.