The other component of getting a ratings bump that has not been mentioned is the weighting of the playoffs for your year end rating. My understanding is that the USTA somehow uses a weighted average of your playoff performance and your dynamic rating to get your year end rating. No playoffs ... and they just use your dynamic rating at year end.
What this means is that players who are bumped usually fall into two distinct categories.
1) Good players that play up .... discussed at length here
2) Good players on good playoff teams.... Because they play in the playoffs these players likely get better opponents and doing well against these good players has a more dramatic effect on their ratings. Essentially because these matches against good players occurred in the playoffs they count double which can help you more.
I think I fall into the second category ... I was good relative to my 4.0 peers within my district but I do not think I would have been bumped had I not performed well in sectionals the last two years.
"You should be playing linebacker, not singles."