Box Cancel Used As Precancel?

I have the envelope below which I can't quite figure out. It was obviously sent as a precancel but the stamp looks to have a box cancel on it. The box cancel must have been applied before the stamp was put on the envelope (if you look at the perforations you can see the ink doesn't bleed on to the envelope). So, it appears that the box cancel was used on stamps before applied to be used as precancels. Am I interpreting this correctly, and was this something that happened regularly?

Your interpretation is correct. These are not common, but not sought after by precancel collectors.

Lots of postmarking devices were used provisionally to precancel stamps. I agree with Chasa that the rectangular box cancels are less common than other devices. Here is a box from Geneva, Indiana used to precancel a pair of stamps used on 3rd class mail:




Use of non-standard devices for precanceling seems far more common on postage due stamps. Here is a steel handstamp used on dues at Terre Haute, IN:


A boxed parcel post roller cancel to precancel a due stamp:


And a business reply mail cover showing a combination of normal precancels and stamps precanceled with a parcel post roller cancel from South Bend, IN (and a combination of two series of due stamps):

Thanks for the info. Always good to learn something new!