Did you measure them with the weight of the truck on them? I'm sure that would squat them at least 1/2", if not more. When you say the width was just under 11", were you measuring the tread itself, edge to edge? I think the mfg includes the sidewall ballooning in their specs but I'm not sure. I don't remember exactly but when I measured the tread on a 35x12.50R18 KO2 it was definitely under 12". Tires still looked huge up close though. I didnt think to measure height but wish I had now.
In for more pics, especially pics of the tread width.