once you go past 3 genes, its faster to use the calc, im not drawing 64 boxes lol. personally, I can still do 3 in my head pretty fast, but not alot of people can. its nice to have a full layout calculated for you, nice a neat, no boxes to add up and all that.
When you start doing super pastel/spider/pin/het hypo to a pastel/pin/hypo/black pastel, your looking at alot of time. lol