I'd like to be able to override the default shipping amount.
The system estimates shipping based on weight but doesn't seem to account for other things like the size of the box when shipping larger orders or large items. I've run into a few scenarios where my proposal gives me a shipping number that's too low but there's nothing I can do about it other than and an 'extra shipping' line item (which looks really stupid and just raises more questions on an invoice) or create a flat rate shipping option for that, or a close enough amount. I'd like the option just just enter my own number if I don't like the one the system generates.