Seems more like an implementation detail than a "we're trying to sneak DRM back on you" thing. If the users had paid the $0.30 to upgrade the track to DRM-free

Seems more like an implementation detail than a "we're trying to sneak DRM back on you" thing. If the users had paid the $0.30 to upgrade the track to DRM-free, they wouldn't be getting a DRM track. When they purchased the tracks for $0.99, they had DRM. Now new tracks generally go for $1.29 with no DRM. There is no way to skirt the $0.30 fee for a DRM free track. The $0.30 is the record labels' tax on everyone for the small percentage who share their music.