One of the wheel makers that has building info recomends this for rear wheels, forget who it was though. The theory is that a large part of the problem with dished wheels is that the side with the lower slope, therefore lower stress is not very tight compared to the other side (which would be the freewheel/cassette side for the rear, or the disc side for the front). As a result the low tension spokes tend to get loose, and truing or tension problems set in, then maybe spokes break. His view was that this often gets blamed on the loads imposeed by the wheel being dished. But in his view the root of the problem is that the wheel loosens as a result of the tension on one side being too low. If different gage spokes are used then there is a better chance of the wheel staying tight.
"The grade or type of steel does not determine the stress that is on it."
No but gage of the spoke is the wire thickness not it's grade.
"Stress=pressure=pounds per square inches = pounds of force divided by the cross sectional area of the smallest part of the spoke."
Right, so a thinner spoke is working closer to it's limit when under the same force than a fatter spoke. It get's more stretched out and is more likely to stay tight. Or so the theory goes.