I've been doing the PE thing for a little while now. I measure my length pressing a ruler against my pubic bone and measuring across the top. I noticed the other night though, that when I use a measuring tape instead of a ruler, my number's .5" shorter. I put my fingernail on the 0 line of the tape and press to my bone. It seems like the measurement should be the same...or at least not that much different. Has anyone else experienced anything like this? Any ideas why?