Being a humble student at the bottom of the aviation food chain, I hesitate to voice an opinion, but here goes anyway.
I felt sorry for the FI who posted the topic. I have flown with 6 different instructors due to weather, holidays, available slots etc. Personally, I have found there are differencies in the way some things are taught. My attitude as a student is to fly the way my intsructor tells me to during a particular lesson and then after I'm back on the ground question my instructor about differencies I had noticed and ask him why he does it this way instead of that way. Then I go home and evaluate the different techniques and decide which one I prefer for myself and (more importantly) why.
We are always told as students not to be backward about coming forward and questioning decisions made by more experienced PIC's be they FI's or PPL's. That doesn't mean we need to pick an argument with them or make an issue out of an instruction during a lesson. I think instructors have a difficult enough job at times trying to get us students our wings, so why make it any harder by being awkward.
Presumably nothing you are being taught is dangerous, just different, so conduct the flight in the way that your instructor on the day instructs you to, then evaluate what you've been told and make decisions for yourself afterwards.
Well, I think the old grey cell has had enough. Off to try and make some sense of my confuser (might be a good idea considering I'm supposed to be sitting my Nav exam this week - oops!).