No,coupon will always be+EV
off the top,
coupon value ~47% == 4dollar 70cents
at hi-lo +6, coupon value=50%
of 10dollar == 5dollar
normally i don't bother much about mps but i do use them mostly on table max bet in order to get more money than table maximum(which is pretty low in my local casinos)..
best game to use mps are baccarat banker bet..