That said, there's a bit of a problem...
See the skill difference between A+ and S is ridiculous, to the point where several players (myself included) are stuck in a limbo where A+ matches are usually easy as pie, and S matches are tough as nails.
I've personally reached S rank over 7 times, but could never keep it longer than a week.
Since this limbo's pretty hard for me to get out of, I've kinda just said "Stuff it, I'll never reach S for real."
That's not exactly the kind of thing I want to have happen with Splatoon 2 just around the corner, and with no real way to train with proper skill levels, (keep in mind that I have no squad) as opposed to slight varying ones online, I've kinda just given up.
For reference, see here:
http://www.evanmiller.org/splatoons-ranking-system-is-still-broken.html