Cloning Shipping Modules

Is there a technical reason to rename the class and function names when you clone a shipping module, or because it's easier (and safer) to rename everything the same? I wasn't sure if the class and function names are local or used outside of the individual module.

The renaming prevents issues ... example a clone of Flat Rate flat would use:
flat.php goes to flat2.php
flat goes to flat2
FLAT goes to FLAT2

Or something like:
flat.php goes to flatusa.php
flat goes to flatusa
FLAT goes to FLATUSA

as long as you follow case sensitive renaming you should be fine ...

I followed your instructions from an earlier post because I wanted to have a freeoptions module with price > x and weight < x, and only for the lower 48 states. I did see why changing both comparisons in the final check from OR to AND caused an issue. If the value fields are blank for both fields for items, it defaults to false which works fine for an OR but not an AND. Another tip, if you use an editor like UltraEdit, you can set the Preserve Case option. This allows a case insensitive search, with the replace matching the case of the found value.