Okay, I just hooked up my dock to my SPro3. I connected the two 4k monitors (configured to 30 Hz in the SPro3 previously) to the dock and the 1080p to the SPro3, the opposite of what I had before. After changing the connector around, it came up just fine. So I can get rid of the MST hub I had (and the SPro3 Dock). Looking at change display settings, I do not even have a 60 Hz option under advanced. So I am pretty sure that the dock has an MST and just one DP 1.2 link.