John, thanks for your response.
Weld is in the flat position and access to the root should not be an issue. The engineer on this project assumed symmetry was mandatory and asked me review the code and make outside inquiries. Your response has reinforced my comments to the engineer.
A very good question. 3.13.1 Joint Dimensions addresses limitations. Symmetry is assumed, but since there is no centerline shown through the joint detail, and without dimensions to indicate symmetry, it seems to me that as long as the groove angle is within tolerance, it's still acceptable based on no opposing code verbiage. However, you may want to run your question by the EOR to see if he/she might take issue with the 15/30 configuration, but like John, I don't know of anything that won't allow it, although it's not something we practice. We base our groove angles off the joint centerline on everything... doglegs, etc.
Edit:
You posted a response as I was typing mine.