Turns out though, there is a downside. I was wondering why I needed to stack the outer scoring blades (.25) with a 3/32 chipper (.09), a .020 shim and a .005 shim, .365 total, in order to get a 3/8 (.375) thick cut. I had already tried going the scoring blades with a 1/8 chipper, and that ended up oversized. So, I did some checking and noticed that the scoring blades had some wobble, and by some im mean nearly 15 thousandths near the blade edge.
My saw doesn't have any measurable run-out on the arbor, at least not with the tools I have to measure it with, and my 10 inch craftsman combo blade measures less than 5 thou run-out an inch further out than I tested the dado blades at, so it's definitely the dado that's off, not my tools. Given that the 2 blades are the same maker, something tells me I just got a dud with this dado stack.
So, alas, this ones getting sent back to Sears. I'm going to try exchanging it, because even with the run-out issues the stack preformed extremely well, shocking well when considering the run-out actually. I'm hoping I just got a dud this time and the exchange unit will preform flawlessly, but until then I'm afraid I'll have to retract my recommendation