I just printed the label for a hardback book.  PBS estimated it at 1 lb., 8 oz.  Amazon says 1 lb., 4 oz.  So, for the first time ever (I'm still a newbie--2 months), I changed the weight. However, the label says 2 lb. media mail rate.  Can someone explain that to me, please.  Thanks in advance.

Media mail goes by pound. Anything up to 1 pound costs 2.13 to mail. Anything 1 pound to 2 pounds costs 2.47. So it doesn't matter if the book weighs 1 pound 1 ounce or 1 pound 15 ounces it costs the same to mail. Hope that helps :)

Here's something else, just so you know for the future.  Amazon is not always entirely accurate, particularly because they are giving you the weight of the book itself, not including any packaging.  And sometimes their weights are just wrong.  I'd highly recommend that you buy a cheap postal/kitchen type scale and double check your weights that way.  You can buy one in the PBS kiosk, or online or at any store like Target, Wal-Mart, etc. 

Thanks, ya'll.  So, actually, even checking (I did weight it on my cheap kitchen scale, also), it wouldn't have mattered if everything between 1 lb. and 2 lbs. costs the same.  Correct?  Also, since I normally use the PBS printed two pages, I have to make a decision (weight-wise) before I print it off (for any extra packaging weight).  Oh, well, I'm just so thankful not to have to go to the P.O.  It's so much trouble in this town that I probably wouldn't be a PBS member.  Only one book hasn't fit into my mailbox.  Easy going!