I'm going to ask what would seem to be a simple question. Which bottles did you fill first, and how do you ensure your priming sugar is evenly distributed?
When I switched up my bottling procedure I had to make extra sure that I properly mix my priming sugar because of using a 10gal corny. I don't prescribe to the bottle size having an effect. I will sometimes fill many different bottle sizes in the same bottling run depending on the beer. Some of my belgians will get a 3L bottle for a trappist style party I want to have. I've done a 6000ml, 3000ml, 1500ml, 750ml, and 330ml bottles all in the same run all pouring apparently the same carb. Headspace may have an effect but when we're talking volume in a bottle neck we're talking very small amounts. So I can't see the head space making a drastically different carb level in a 22oz vs a 12oz. Also if you're using a bottling wand then your head space is ROUGHLY the same. Sure you have a slightly larger amount of volume displacement because its a taller bottle. However the volume is rather small.
Going through life is hard.
Going through life stupid is harder.