True count conversion

I have to admit I'm addicted to this board! Anyways, heres my question. When using Hi-Lo count, is it necessary to convert running count to true count for every card you are dealt when playing your hand? Or can you convert once when you are initially dealt the hand and stick with that count as you are dealt more cards. This assumes you are using basic strategy variations based on the true count, and the count (running and true) changes every time you hit during your hand play. Thanks very much for any advice...