As the SCF April Rating list is out, I took the pains to compute the performance of my students and here they are. The variance is computed from their last rating in Jan'11. If you compute it from their Jul'10 rating, the variance is even greater.
Generally, the students who were with me for more than 2 years had good gradual increases in rating. Kristine was an exception - her ratings were slipping when I took her on in November last year but she's climbed back to the 1400 level.
As the above students were not involved in the National Junior Squad program since June last year, none of their ratings were increased artificially (evidently when the ratings are rounded to 1200, 1300 or 1400 upon joining).