Dwell readings changing?

Thanks for all the information and suggestions. The timing stays dead on, so maybe the bushings aren't the culprit. Moving the rotor clockwise, there's some play in the direction of travel (about 1/4") and side to side, there's a very slight wobble. I'm a firm believer in "when in doubt, swap it out," especially on a middle aged vehicle, so I'll probably just get a new distributor. And I might just kill two birds with one stone and go for the upgrade.

Any thoughts on this one?
http://www.summitracing.com/parts/DCC-3690426/