Unless I misunderstand I think you are making this a lot harder than it needs to be.
What I did several versions ago was this...
For MLB simply enter the actual stat totals for the year you want, 2015 in your case, and use auto calc. You are done.
Minor leagues I searched for real life data and averaged it over the last 3 seasons and used that as my league totals. Then use auto calc. Done.
I run auto calc on opening day of each level so rosters are set. I do this every year though you can go every other or every three or whatever you want if you want a bit more fluctuation.
Never touch the modifiers yourself, that is what auto calc is for. You only need to put in the actual league totals and let auto calc do the work for you
