You must have had some shit-tier comp resistors. Sure, they drift with time, but a good one will be well within it's tolerance values. I checked a couple of these and they were within their indicated range. These aren't so much for restorations, resistances in older gear can change a lot before the circuit becomes useless (capacitors usually are the issue here,) it's just that carbon comp resistors will burn open if there's an issue, so they're good for circuits where you need that sort of thing.