Getting Rolled at Bullet

The latest issue of New in Chess has an odd little article by GM Danny Gormally on online chess addiction. Now these days I don't play a lot of online 'real time' chess, but I decided to revisit the Free Internet Chess Server. As an aside, I joined FICS so long ago that I was able to use my own first name as my handle (and not shaun64 or shaunroolz etc).
Because I'm a sucker for punishment I tend to play bullet against computers, figuring that I'll get better at it if it isn't a mutual blunderfest. Unfortunately this means I just get snapped, and my last visit was no exception. Playing against Gizmo (2000+) I lost 0-3. The first game I was up a piece, and lost on time. The second game I left a mate in 1 on, and in game 3 I moved my attacked queen along the line of attack, losing it and the game. This left my Bullet rating at a very impressive 1320.
Contrast this with my rating at chessworld.net, which is about 1000 points higher. Of course there the time limits are in days rather than in seconds, and this leads me to the following formula.

For every extra second of thinking time I am 0.0023 rating points stronger.

Of course this is a back of the envelope calculation, and may not stand up to further testing.