There is no need to explain things to a pianist that they already know or understand. For example, if you have just shown an exercise in three, while singing snippets of the Waltz of the Flowers at the tempo you want, there is no need to say “So I’d like a waltz, please, in 3/4, at about this tempo…”.
If you do overexplain, the pianist will come to expect it, and won’t bother to watch your marking, because they know you’re going to come over and say it all again.
To avoid this, when you first work with a pianist, say “I’ll try to show what I want musically when I mark the exercise, but if anything’s not clear, please feel free to ask”.
