Oh! Okay! Ah-ha! So in a tightly controlled work environment where everyone in the main work area in each section worked in view of others, no one noticed that Oswald skipped out for least 25-minutes, even though Oswald was a trainee, huh?
The post office where the money order was bought was 11 blocks from Jaggers-Chiles-Stovall. Assuming that Oswald speed-walked to the post office, that he didn't have to wait in line, and that it took him no more than 2-3 minutes to fill out the money order and have it processed and given to him -- assuming all these things, he would have been gone from his work table at least 25 minutes.

2 to 3 minutes at Dallas Post Office, conservatively.
7.5 to 8.5 minutes to briskly walk half a mile.
So yeah, 10 to 12 minutes late. BFD!


JohnM