What I would add (and probably is of little importance for your case) is that the type "supported dome roof" is not strictly covered by API 650.
By similitude with the definitions given in API 650, 5.10 Roofs, 5.10.1 a supported dome roof without columns may be defined as a roof formed to approximately a spherical surface that is supported principally either by rafters on girders or by rafters on trusses.
I'm not an expert in definitions, in my opinion a better wording would be supported dome plates on self-supporting structure, why not?
Now recalling the last API 650 provisions as valid for this type of roof (quite common in our days, because there is a tendency to rise-up the internal pressure, which means to work with bigger θ than is practical for conical roofs, just trying to keep A as reasonable values), DLR would include all the roof structure not only the plates' weight. This is confirmed by a free-body diagram of roof (a common concept in API 620) and is what I understand from API 650.