Advice for National Series refs

Yeah I don't think calling time that often is useful.

5, 2, 1minutes and ten second count down is enough, isn't it? Also that removes any confusion about which way you are counting.

My personal problem with this is that if I am using a stopwatch counting up, as opposed to a timer counting down, I find it a genuine effort to do the subtraction, so that I can shout 2 mins left etc.