Roadrunner, I don't have any reliable stats on this, however, when looking at form for races...the shorter the time between runs, the more reliable the data.

I.E. If a horse won a race seven days ago and the trainer is prepared to start it again in a similar race, his last win is a consistent guide.

If his start was three weeks ago, I would be wary of the winning form holding up for such a long period of time. I would look at that ozeform site to see if the horse has run any trials since the win so you can be sure it is fit.
Trial times are to be treated as a guide only as they are not raceform. If the horse won the trial easily, I would say it is fit enough not to have trained off though. Trial form is more of an indication of the sprinters.