Yes, actually I did get caught out. I cut the margin a bit too close
(My altimeter showed me about 100 ft above the 500', but I suspect my
altimeter needs recalibration) so lost some points.

A good trick here is to look at the altitude that's being recorded in
the GPS rather than the aircraft altimeter. If you have a 302, the
altitude being displayed on the 302 is the same as being recorded on
the GPS so you know to the last foot exactly what's going on. Most
GPS systems can display altitude, you just have to find where it is
and look at it.

I should have listened to 44 and landed straight in. Less
safe, perhaps, but a better race option.

In most cases, it's the other way around: an early commitment to a
rolling finish is safer than arriving at 501 feet, 1 mile out, and 42
knots, much safer than staring at the altimeter for the last mile or
so if you're unsure you'll even make that, and far safer than
arriving at a finish line over the center of the airport at 50 feet,
50 knots. Was there something unusual at Ionia that turned this usual
advice around?

John Cochrane