The ratings on the site might be out of date... this thread features a link to the most recent ones for the upcoming season.
https://forum.calgarypuck.com/showthread.php?t=183738
The league is run through a simulator called STHS. Pretty standard sim league setup across the board. Ratings are largely based on real life, this season they're based on a blend of the previous two seasons because of the weird sample sizes but they're typically a reflection of the most recent NHL/AHL season.