Shipping Based On USPS and Flat Rate Boxes

[zhylosa]

Is there any way, in general, to say allow the flat rate box shipping option if the item is under a certain weight, to get rid of some of the disparate published vs flat rate box rates?

To allow for Flat Rate boxes I am using the USPS and the table module.
In the table module I have the following setting:

Enable Table Method
True

Shipping Table
2:4.6, 10:8.95

Table Method
weight

Since I have my store is for books, I have the flat rate envelope and the flat rate box listed. When the client checks out they are able to chose either the USPS or the table rate (it normally bolds the best rate).