the main reason to give the new technique a try is because the teacher is evidently using the technique in class and if you 'choose' to teach your gs some other way he will never catch-on and be able to understand what the teacher is talking about. you are setting him up to fail.
when my son was in algebra class years ago he had a teacher that was doing something i thought was ridiculous and took twice as long to get to the answer we figured out (my-way) he struggled through the whole year and even when he had the answer correct he was graded on writing out the whole problem and steps, since he did not follow the steps the teacher taught he was marked wrong on everything. teacher and i went round and round...i could not help him with his homework because i was causing him to fail math. sometimes it seems the correct end result is not as important as the steps you took to get there :wink: