Here is an unusual problem that I'm struggling with. I looked at different extensions and could not find one that do what I need. I need to be able to manually override shipping price for selected method in admin. There is plenty extensions allowing to enter freehand shipping method and price, but in this case I need to be able to override just the price of one of the standard method. E.g. customer calls and we want to give UPS Ground shipping for $5, so I need to be able to manually enter $5 as rate but I need to have the ups_GND as shipping method in the db. Any pointers where to start coding something like this?
You can use a flat price shipping associated with a customer group. You will need to code an extension to apply/activate this method to only one customer group, but it might actually work.