I really think you are on to something! I just took these pics of mine. The first one is the one I sent you the cuttings from. It will probably drop half the buds on this branch.
The pink one is also in a 15" basket, but a bit was higher, with more sun, and it's blooming.
German Empress ( I can't spell the proper german name), Blooming, but has looked half open for two weeks now.