At my firm, we use Nancy's method.  Another option would be to set up a separate bill layout, and simply add the other address in a text box somewhere.

Let us know if neither works for you, or you need help getting it going.

Good luck.

-laurie

Shouldn't it be a common enough situation for Sage users to bill a client that is subcontracting them?  Why should users have to make up a work around?  What happens when a new admin person comes into the company and needs to be taught all these silly workarounds to poorly thought out design? Someone has to invest time and money into teaching them or (shudder) they design their own work around making for even more confusion.  Should users get a reduced rate for the software based on the number of hours they've spent creating and transitioning new users to their workarounds or should users as paying customers expect the product to perform the way they need it to?

Shouldn't it be a common enough situation for Sage users to bill a client that is subcontracting them?  Why should users have to make up a work around?  What happens when a new admin person comes into the company and needs to be taught all these silly workarounds to poorly thought out design? Someone has to invest time and money into teaching them or (shudder) they design their own work around making for even more confusion.  Should users get a reduced rate for the software based on the number of hours they've spent creating and transitioning new users to their workarounds or should users as paying customers expect the product to perform the way they need it to?

Funny you should ask, in Timeslips 2015 additional client address field functionality was added to the software.  Perhaps you want to consider upgrading your software?

Wow Workaroundhater, I just realized that I answered an almost 4 year old post due to your rant!  How long have you been working with software?  Do you actually think it is possible for developers to get it right for every conceivable scenario that users might encounter?