No mistake.
A 30 mm is a 30 mm is a 30 mm. No matter how small or large the format, and not matter whether it fills that format or not.

Especially when macro is concerned, a lens' focal length matters more than an angle of view.
Try to do 1:1 with a 1200 mm lens. Very, very hard. No matter whether on APS or on 8x10".
Try to do 10:1 with a 30 mm lens. Easy! On APS, Full frame 35 mm format, MF, LF.