The answer from Mercury is this:

You cannot order a Pro XS with the sportmaster...only the Verado or the Torquemaster. However, you will find many dealers that will swap out the lower for the sportmaster for a cost. In fact, my 250 Pro XS has the sportmaster case and I paid extra for the swap when I bought it.

The Pro XS has "semi hard mounts" that are almost identical to the hard mounts on the XS.

They are made in the same place and the differences above and the warranty are the major differences.