By calculated value I want to subtract the count of two measures from the count of a business transaction and then display this value. Sounds sttraight-forward but I can't see anyway to do this.
Great question! Currently to my knowledge, there isn't a way to explicity calulate a value using seprate measures other than creating a 'Rate Measure' (division).
It might be possible for you to work around this by creating a copy of that Business Transaciton you created, but somehow it filters out those two measures?