incorrect weight + shipping cost comparison

I'm moving a customers storefront from a network solutions hosted package to a zen cart installation on their web site.

Two questions ...

The item I'm testing has an assigned weight of .80 lbs, but it shows up in the cart as:
United Parcel Service (1 x 3.80lbs). What could be causing the weight to be incorrect?

Secondly, when I compare this item in the current network solutions cart (which also has an assigned weight of .80 lbs), both using the UPS calculator, the shipping costs differ.

Zen Cart = $20.10
NS = $17.77

Thanks,
david

p.s. this is a new installation of 1.5.1, done via FTP
PHP Version: 5.2.17
Database: MySQL 5.0.32-Debian_7etch6

Check this for the first, and maybe the second:

http://www.zen-cart.com/content.php?127-my-shipping-is-figured-wrong-it-is-3-pounds-too-heavy

Thanks! Changed the tare to 0:0 and the prices now match across platforms.