Just our experience--our DD has a *ton* of problems with illogical and/or unexpected consequences. And we have been in Montessori the whole time (now starting fourth grade), but at two different schools and with different teachers each year for the last four years, despite the three-year Montessori class structure. In our experience, there have been two kinds of Montessori schools and teachers--those who are very serious about the Montessori philosophy, particularly grace and courtesy, and who respect the children, and those that to us seem to have the Montessori label without any of that. The teacher quality at the one school that we just left was all over the place--we had two wonderful years there, followed by an absolutely awful one last year in which the 'Montessori trained' teachers basically imposed illogical and unexpected consequences as you describe, except not keyed to a color chart. As an aside, it also irks me that Montessori schools get talked up so much for math--I think the system is great for teaching concrete --> abstract, but once you get beyond that there doesn't seem to be much and it's up to the individual teacher to teach higher math, and if they aren't interested you're SOL with the school, so we've been using EPGY since last year. We came to find out that a lot of DD's classmates were also doing math outside of school, which surprised me given the way the school talked up their math curriculum. Anyway, I guess my point was just in our experience it is really the teacher that matters the most, and that Montessori can mean a *lot* of different things in terms of how the classroom actually works. I really wish there was some way to figure out beforehand how one's kid would work out with a particular teacher, but we haven't found it yet. I really hope things go well for you but I don't have any helpful advice except that it might be better to leave if you can than to try to make it work where you are. Best of luck!