Four years later and QBO still has not added this simple feature.

We have the same issue.  We use (as QBO designed it) the mailing address our vendors request to mail our POs and the shipping address to say the location for the materials to arrive or where the work will be performed; this is standard practice for many businesses where the location of the work is different than the location of the requestor of the work to be performed.  Then when the 1099s are created by QBO, they show the mailing address for all of the 1099s which are not the same as what our vendor's W9 says.  We need a spot to put the 1099 W9 information for the vendor so when we run a 1099 report, the company name and address on QBO's 1099 report matches the actual information required for the 1099.  If our vendors all used the same information as their W9 for their POs, this would not be an issue, however our vendors do not work that way and we need this flexibility for ease of use. 

It is not hard for QBO programmers to add a separate 1099 email address on a vendor to be stored for 1099 purposes if the 1099 checkbox is marked off for that vendor and then update the API also with this feature.  We can't use your 1099 processing you offer because of this error in your reporting so we have to use third party software for it.  Please QBO add this feature so your reporting features make sense.