% Physical Complete doesn't roll up because it doesn't make any sense for it
to. If it did, any numbers it produced would be meaningless. Consider, to
build a birhouse I need to cut 7 boards for 4 walls, 2 roof pieces and the
floor, an opening in one wall. I need to nail them all together and then
paint. I've cut the walls (100%), painted two of the 7 pieces (30%), nailed
two walls together (20% of the nailing). What is my summary physical %
complete and if I *could* come up with a number, would it mean anything
regarding how well my birdhouse was progressing? % Complete refers to
duration worked versus duration required, a far more accurate measure.