It seems to me that what is slowing the spreadsheet down is that each time you enter a number in a cell at the top of the spreadsheet, it recalculates all of the formulas at the bottom. If there are 750 employees multiplied by four jobs multiplied by the number of stats being tracked (feet, hours, weeks etc.) then that takes time. Seems that what would be preferable would be to have the spreadsheet wait until you have put in the values in the cells at the top before it starts calculations in the formulas at the bottom. That being the case you might consider point number 9 in this article, which is about setting the calculation mode to manual.