I am knitting a jumper for my boyfriend (yes I am ignoring the curse) and I swatched it ages ago. I knew that my tension was a little large. I made a square 50 stitches wide and the desired tension was 22st and 30 rows to 4 inches square. If I had only made the 22 stitch wide swatch it would have lead me to believe I was spot on but obviously even a small bit out over such a wide piece adds up to a lot. I can't remember what I actually got but it wasn't too badly off, about 22 st to 4 1/4 inches.
I didn't want to change down a needle size as I only have 8 balls of yarn and smaller needle size means more rows so in my head that meant more yarn. I decided to follow the instructions for a 42 inch jumper to make a 44. I decided to make it in the round instead of flat so I took away the extra 4 stitches and got 244 for front and back. Well after I got to the armholes (17 inches of knitting later), I put it on longer circular needles and put it on the floor laid out and it was 48 inches around. Even allowing for a little extra room that's way too much. So if 244 stitches came out 48 inches I reckon that 222 stitches will be 44. The instructions for a 38 inch jumper would be 220 stitches if made in the round, so maybe I'll just follow those instead. He's wears a size 42-44 but in real life he measures 38 inches around the chest, so it wont be too neat. Does anyone else follow my random logic and fuzzy maths?
So sorry you had to go through all that trouble! Day before yesterday, I had to frog some socks I'd been working on for 4-5 days. I was 3/4 of the way done, tried them on... they didn't fit! They looked awful! I feel for you.