Amusingly, I discovered a method very similar to this in college. My method was simpler - stick a 1 in front of one chemical, then you get an n x n linear system of equations for the remaining compounds. Solve it, then figure out what to multiply by to get an int solution. I suspect that my version isn't stable, which I gather is the problem these guys are solving.
I was forbidden from using this method on the final, since it isn't the ad-hoc method that was taught.
This reminds of my first chemistry class in high school. Everything in the beginning seemed so trivial that I tended to not pay attention at all. I had my own methods for various things (including stoichiometry like you).
Then the first test came. I seemingly had no problem with it. A few days later, the tests were returned. Everyone got theirs back except for me. I was summoned to the front of the room and the teacher asked me to explain how I did things. We went over the first problem, she understood my explanation. The second, same thing. I was continuing my explanations and she cut me off--"Forget it; I trust you." She flipped the paper over and wrote 100 on it and gave it to me.
Boy did that make me never want to do any work in that class again. Apparently I and the eventual valedictorian of our class were real pains in the asses to her. We were "punished" by being given a box of magazines (Scientific American, etc.) and told to sit in the back of the room and not talk.
I apologize, Ms. M., for being nuissance, but I think this was a fair treatment rather than being scolded for having my own ways of doing things.
Anecdotal evidence suggests to me that this is actually all too common. When I describe my primary and secondary schools (1970-1974, Park Senior High, etc., Swindon) where challenging teachers with difficult questions and alternative methods simply prompted the teachers to either gently shoot down your naive idea or return the challenge with something a bit more difficult I am often told "That's how it worked at your school, the rest of us didn't have it so good."
Did you ask if it would be alright to use your unusual method and only then had this method disallowed, or did somebody forbid you from using it after eg. seeing you use it for homework?
I wonder if they did it purely to reduce the workload of the TAs which will be grading the finals, or did somebody think it would be wrong to have an unorthodox path to the result.
I was forbidden from using this method on the final, since it isn't the ad-hoc method that was taught.