Bridgestone HP Sport Discrepancy??? Need help!!!

[catgo]

I'm in the process of upgrading my wheels from 19'' to 20'' and I'm therefore shopping around for tires. After searching in tire rack for a while I noticed a discrepancy between 2 bridgestone h/p sport tires, just different in size. I noticed the width of the smaller tire (255/50) appears to be greater than the (275/45), screenshots are included....please notice the "section width" and "tread width" of these specifically!

Anyone has any idea why this happens, I also noticed that the current tire I have 255/50 RFT appears to have a wider section width and tread width than both!

I'm currently deciding on which tire to buy but I thought that going from a 255 to 275 tire would mean a wider tire! Is something wrong here?