You actually don't have to be at High to sign a recruit.
With my D-3 program I had a recruit I offered in RS 1 and was at Moderate. As soon as RS 2 started an ACC school came in and obliterated me. I fell to Very Low and stopped recruiting him altogether. Well the ACC school who was Very High never offered, nor did any of the other 3 D1s (I'm assuming the ACC school scared them away as well).
I went to bed that night thinking I had 2 walk ons. I woke up the next morning to find that recruit had signed at 2am after recruiting closed at 11pm.
At the close of recruiting if you have scholarship offer on the table and an open scholarship available the recruit MAY sign with you if he doesn't have an offer from the HIGH/VERY HIGH category. I got a High major prospect at a D3 program with a Very Low interest rating.