My best guess is the game "autocalcs" every time you select a year, whether different years or the same year over and over. This will result in LTMs over a range just because of randomness, I would think.
Why would it work this way and not be 1.000? Again only my best guess...
It is so a player can simply select the year and start playing and get stats in line with the LTs. If it defaulted to 1.000 the stats could very well be way off since all leagues have players with different ratings. Imagine a new user coming in, he\she isn't going to have a clue why their game is producing such unrealistic stats but.... if the game automatically adjusts LTMs for them on selection they should be "good to go".
If that's wrong someone will be along to correct me
edit: I didn't mention specifically your "middle section" question. I think this too is just random to how the game autocalced, IE each time you hit it randomness in that simulation came up with differing stats (SB, DP, etc.) and adjusted the modifier accordingly.