I have a 26.8 seatpost near to hand and there is no way that fits in, whereas the 26.2 (my calipers flits between 26.1-26.2 when measuring it) fits quite snugly. I don't see any deformation of the seatpost and neither did the my favorite bike mechanic when I went in for a chat about it this morning (though we really weren't looking at the seatpost though at the time)

I'll double check in the morning though for anything funny along the seatpost.