Meters also drift due to certain variables. An internal meter in a camera might not be the same later
as when it was new. Also be aware that even doing something as simple as changing a focus screen
in an SLR can skew the readings. The most important point is consistency. If you have to, you can
offset your ASA setting a little to compensate in relation to your other meters. But I suspect it's
easier to get a basic handheld meter recalibrated than something inside a camera no long in production. I keep on hand a brand-new Pentax digital spotmeter just to check the ones I actually
use (and as a reserve when one of them finally wears out). They only need recalibration about every ten years, and I get it done in Hollwood for about a hundred bucks.