I am interested in comments regarding the reliability of two different scenarios for constructing a wheel with a medium section alloy rim (say 27-28mm deep) and internal nipples:
Scenario A: Using an unslotted standard style nipple that is inverted, and a spoke length where the threaded section of the spoke bears against the actual wall of the rim.
Scenario B: Using a nipple that has a counterbore (doesnt matter if hex or standard) so that where the spoke passes through the wall of the rim it is unthreaded and the counterbore allows the nipple to make up tight without bottoming out.
If my descriptions above are no good I hope my sketch illustrates what I am asking about.

To me scenario A seems like asking for trouble as whilst the spoke is loaded in tension if there is any flex in the rim this will create a shear loading on the spoke and the threaded section of the spoke where it goes through the rim is a stress raiser crying out "Snap Here Please". Scenario B will still see the same loadings but moving the threaded section of spoke removes the obvious stress raiser, am I correct in my thinking?
For a bit of background I weigh 180lb and have been riding a set of homebuilt Kinlin XR300's 20F, 24R (2X) made with some ACI bladed spoke and standard non internal nipples and not had troubles with spoke breakage, I also have a set of low end Shimano factory builts 20F, 24R (2X) with standard type nipples and have not been breaking spokes.
The problem is I have just bought a new bike with set of Roval Fusee EL28's which are 20F, 24R (DS= 16@2X, NDS=8 rad) and and in less than 1000km been suffering multiple broken spokes on the rear drive side. I think that the reason for this happening is that the wheel is built as in Scenario A and where the spokes keep breaking is the point where the threads of the spoke pass through the rim. Every time it has happened there has been about 1mm of thread attached to the inverted nipple and there is always about one thread left on the end of the broken spoke.
Thanks for your help.
Mods please move this to the wheelbuilding topic if you don't think it deserves its own space.