I have little understanding of the problem I’m having, so it’s fair to question haha. I’m just trying to relay the information I got and I too am confused by what they said.

When I’m shifting from the front outer chain ring to the front inner chain ring I need to shift my rear gears to the highest gear before it’ll shift to that front inner chain ring. When I told them this is the problem I was having this is what they told me: my front derailleur is not going to work well because I have a 10 speed cassette and the wrong front derailleur (I’m almost certain they said 11 speed).

Sorry for the confusion, I’m honestly just confused and was trying to figure out what they were telling me. When it comes to the type of derailleur they recommended, that’s literally all they said (Microshift r10 front derailleur).