Scout and Rivals both do it off of some sort of points system they've devised and not off of the average stars recruits get. So a team with a higher total number of recruits can rank higher than a team with fewer, but higher rated recruits.
Scout has Texas ranked #1 with 23 total commits, 5808 points, 7 top 100, 5 five star, and 11 four star recruits with total average of 3.87. FSU is 9th with only 15 commits, 3843 points, 6 top 100, 4 five star, and 8 four star recruits for a class average of 4.07.
Over on Rivals, Texas is again ranked #1 with 25 total commits, 2368 points, 2 five star, 13 four star, and a 3.64 average. FSU is ranked 4th with 16 commits, 1831 points, 2 five star, 9 four star, and a 3.75 average.
So I'm guessing that other schools have been signing more people also. Interesting that the two sites have different numbers for the total amount of recruits for the two comparison schools.