John asked, "What does the "Number" column represent? If I have a (Labor Type) 'crew' of (number) '3' at (Hourly Rate) '$10', and put them to work wouldn't the (Labor Cost / Hour) be $30. Hope you can see my question in that :)"
I agree that the labor cost calculator is not very intuitive. The Number column does represent how many people there are of that labor type, but a labor hour is considered to be one person working for one hour or two people working for half an hour, etc. The Number column only affects the Crew Average labor cost. It's a weighted average, so if you have 100 people at $10 and one person at $15, the Crew Average will be much closer to $10 than $15 ($10.05, actually).