Knitting disaster!

I spent my ONE measly day off working on Elizabeth Zimmermann's Hurry Up Last Minute Sweater (see December in her book, Knitters Almanac). It's knit at a gauge of 2.5 stitches/inch and I had already joined the sleeves to the yoke and was cruising for home. I figured I would knock it off my needles in an hour or two. If you're familiar with this sweater then you know the yoke decreases come to a point miraculously at the neck edge. I realized something major was amiss when I still had 106 stitches on my needles after many rows of decrease. I calculated the distance from the underarm to my neck would be 2 feet, 1 inch. Dang. I'll admit I thought some less than respectful thoughts about dear EZ, may she rest. After much puzzling and musing I realized I had cast on 126 stitches to make a sweater adequate for a person with a 50 inch circumference standing 7 feet, 7 inches tall. Why?!!