The only time I discuss it in pregame is if my partner is from Europe. If that's the case, I remind him not to count in metric.
Seriously, if you timed your count at 10.5, I wouldn't worry about it. Better a little long than short.
At least that's what I told the girls in high school.
Back to seriously, I think it would be pretty hard to be way off on a three-second count.
Which is what my wife says she does during sex.
OUCH!