What is the deal on signing numbers

Tennessee was way under 85 2 years ago and back counted a ton of kids last year and the same this year. Its catching up now and for the next couple of years they'll be at 25 or very close to it. They also took advantage of the new "blueshirt " craze that is becoming more and more popular. Those kids aren't counted as initial counters, at least as I understand it.

This is how I understand the blue shirt and anyone that can make it more clear can feel free to add to it or correct.

A kid cannot take any official visits nor have any in home visits. Basically designating them as non recruited athletes(even though they are clearly recruited). They enroll in August without a scholarship, technically as a walk on, and then in the 2nd day of fall camp are awarded a scholarship. That scholarship is only counted towards the 85 and not the 25 initial counters. Basically its a walk on being rewarded a scholarship.
The part I don't understand is how this gets around the 2 year walk on rule for scholarships not. Basically the rule that forced Elliot Porter to go 2 years without a scholarship. His may have had to do with an inter conference transfer I'm not sure. Regardless the blue shirt is what is being used to skate the 25 number while helping reach the 85 number. USC is also using this method to catch up quicker after their sanctions. Of course you have to be selective which kids you attempt to use this with since some will feel disrespected or just turn it down. Its interesting regardless.