I wouldn't count on getting it perfect every time, but there should at least be a difference in consistency. You should at least notice a difference between just mashing A+B arbitrarily and timing A+B at the very end/beginning of a second. You might end up going into PB more often trying to time A+B.
Could you look into Dampierre's "random" moves? I believe that there's a correlation between Dampierre's move outcomes and the timer. Just see if you any patterns or tendencies; if Dampierre's moves are truly random, tendencies shouldn't change.