I'm not sure you can count on a linear progression all the way up to 500. In my experience you hit a level where you're approaching the limits of your body's ability and the progress slows WAY down past that point. When I was lifting heavier regularly (I had partner I was working out with who wanted to lift as heavy as he could all the time), I got to about 350 1rm and my progress got extremely slow after that. It took me as long to get from 350 to 365 as it did for me to get from 275 to 350.
I've never been that strong on bench. I guess I'm not really built for it. Even getting to 365 was pretty incredible for me. In the same time frame my workout partner got to the low 400s 1rm. I remember he could press 405 for a triple, so I guess that puts him at around a 415-425 1rm. Even though we were doing essentially the same workout right up to where his strength surpassed mine, I never manage to gain any ground on him.