Oooh a question! And one I can answer! Since it might possibly be of benefit to someone someday who stumbles upon this I'm answering here rather than in the comments.
All good points. I know I get different gauges with different material needles despite them being the same size (nominally, if not exactly) so that might be the answer, except that both socks were knit with the exact same physical set of needles. The socks are only on different needles now so that I could use the ones I had been using to knit the first sock's foot to knit the second sock's foot for a bit. (Did that make sense? Both sock feet were knit with the longer needles showing on the striping sock on the right below.) And, the needles that are holding the first sock are the same brand and type, just shorter in length. So it's all me somehow. I actually measured properly and it looks like the striping sock is the ever so slightly tighter gauge one. Since that one is the second one I knit, that means I must be more tense (or better at knitting to a tight gauge) now than I was in the beginning. I wasn't feeling more tense so far as I can remember, but I might I suppose have been better at remembering to knit tightly.
Speaking of Maia, she sent me the prettiest skein of yarn as a prize for guessing (wildly inaccurately apparently) the number of yarns in her Way Back sweater. It's a beautiful sweater. I'd kill to knit that well (well, not literally - probably - so I am safe out in public even around good knitters) so go look if you haven't yet. As soon as I saw the yarn I asked it what it wanted to be, but it was shy. I had to agree to wind the skein into a cake before it would speak up. Of course only after winding did I realize I should have photographed the skein before I wound the cake. I've never been good at delayed gratification (or documentation for that matter) so all I've got to show you is the yarn cake. Doesn't it look pretty though? It says it wants to be the collar and cuffs of a sweater. I'm willing to go along, but I don't know if I have an appropriate yarn for the main part of the sweater. So I'm queueing it up but not holding my breath.
As I said before, the socks were laid aside for the Spring Things Shawl shortly after that photo was taken. I think it is safe jinx-wise to talk about that shawl here now, though I am still not positive I'll make my deadline. I've got this so far:
It looks very little like the pretty shawl pics that others have. It'll look much better (and bigger) when it is blocked (I hope/expect/plea). I am loving knitting this shawl even though the time constraint makes it a tiny bit stressful. I have two more repeats of the first chart to do and then I go into the chart with the beading (in my case, or nupps for some of the other folks). Being a slightly compulsive engineer type, after the first couple of repeats of the first chart (I'm amazed I could make myself wait that long) I made a quick spreadsheet to chart/predict progress and thus far I am about 3 and a half days (or about 6 1/2 hours of uninterrupted knitting) behind. I think I can still make my deadline since I padded it a bit. But only if I keep on schedule from now on. Or better still, make up some lost time. When I finish this one I'm totally starting a second one for me. I might make the minimal version for my daughter too since she thinks it is beautiful and thus wants one of her own. Or better yet, make her make it for herself. I can help or even do the actual lacy chart bit but I think she could probably manage, with help, the mainly stockinette portion for sure. She'll probably turn out to be much better at lace than I am. She's very good at seeing patterns so charts will probably be easy for her to memorize.
External influences are making my goal to finish the first shawl on time somewhat difficult. Well, not so much external, since it's all my own fault. Knitting time this week was lost to my own inability to limit my interests. And/or manage my time. Firstly I lost more than an entire day to the first day of an upholstery class I am taking (redoing a chair for my "studio" - chair and studio might be done about the same time some 3 months from now if I'm lucky) and the following day of hands too sore to knit. Secondly I am losing time to attempting a trompe l'oeil effect (a tree in one corner where we have a pipe running through the room) in my DD's new bedroom. I am not an artist. Probably not at all, but definitely not with paint. Still, we're hoping for the best, and lucky for me she is not a critical judge. Luckily for my ego she's still in the "whatever Mommy does is beautiful" stage. Though this tree may mark the end of that. We'll see.