For a step/decoction I would use 131*F then straight to 152*F for sacc rest.
What you did will work fine as well, it's just a little more complicated. Step mashes are always hard to hit your temps, since there are so many variables (biggest one being the heat absorbed by your MLT) so a good rule of thumb is to have 20% over what BeerSmith says at the ready in case you miss your temps.
This should come out nice n tasty. I love a good Helles!