Watching the blackbelts is also confusing because they don't actually do what they're saying to do.
I think that answers your question..
IMHO, people who can't stay consistent with their own words are not very competent. so I suggest that you stick to what your Sensei told you. but to avoid unnecessary conflicts, when in the presence of those blackbelts, you can pretend to agree and try to do what they say.
trying different things can give you a richer experience, though.. so you probably want to decide which movements are more comfortable for you after experiencing them yourself..