iu means international unit. the 1,000 iu is the amount in the vial. the vial also has been reconstituted with one ml of liquid. thus we are converting our measure of iu's into ml. thus to measure the 10 iu's we are measuring 0.01 ml of liquid, or one mark on our syringe.
if you reconstituted with more liquid, the conversion would change. i'm not going to do that here, because it may confuse those already confused. i understood muscle mechanic's rant, as i understand ocd all too well. we just didn't have a name for it back in my day, lol, nor one for adhd.