I think I'm going to have to frog

I'm still here, and believe it or not, doing some knitting. Unfortunately, I've been in denial regarding my gauge on this project for awhile, and have finally concluded that I'm going to have to rip. Rats.
This is the body of the Ski Jacket, from Veronik Avery's book Knitting Classic Style: 35 Modern Designs Inspired by Fashion's Archives. Nice, n'est-ce pas? Only problem is, it's supposed to be 14 sts to 4" and I'm getting about 13 or 13.5 sts to 4". So the whole thing is going to be at least 3" bigger around than I want it to be. Gauge swatch? Um, no, but I did the sleeves first and they were right on for gauge. They are knit circularly, however, and the body is knit flat. Who knew my gauge would be off by that much changing from circular to flat knitting?
This is what the yarn used to be in a former life:
I don't remember where I found this sweater pattern. I do know it was early-to-mid-80s, and the yarn was from a going-out-of-business yarn store. The color pattern is slip-stitch. I don't like the pink. I'm not even including it in the reincarnated sweater, though I am using the grey and light grey. The pockets added bulk around my middle. I gave this sweater to my mother, who gave it back to me in September ("it's itchy, and I just don't wear it"). Black isn't really a good color on her, anyway.
I'm still trying to convince myself that I should frog. The yarn is Lopi, which is single-ply, and has a tendency to pull apart. Fortunately, felted joins work really well, so all of the little balls of yarn from the original frogging session have become one long strand as I knit.