it all depends on how you are built for the most part.. some people naturally excel at rep work, like myself, so it's very easy to hit true 8-10RM's without any acclimation phase.. other people will struggle. Also, my 10RM will always overestimate my 1RM because of how good I am naturally at rep work... it's not good to use 10RM anyway to predict 1RM so i guess that point is moot anyway.. but the same applies to 5RM so I guess it isn't moot heh.. my 5RM will always overestimate my 1RM based on how I am built naturally. I recover better between reps than someone who is pure power for example, I can hit multiple grinder's in a set whereas someone who is really powerful struggles to even finish one grinder.
dno just my 2cents.
pc