Apparently so. I made the jump right from the old Mill Pro to the new Mill Expert, so I can't fill you in on what you'd be getting on a straight across upgrade, but you can also test drive the upgrade versions for 30 days or your money back, in case you try it out and find it doesn't suit you.
It is not clear from the feature list if you would get the "Rest machining" capability in Mill ProfXP. You might want to inquire about that one, because I think that could most easily pay for itself in time saved. It allows you the potential to use larger cutters to machine broad gentle curves, and then to find out the detail areas that need machining later on with a smaller cutter to ensure adequate stock removal in areas where gouge protection would not permit the larger cutter to enter.
I sort of used this feature just lately to check the cutter size I intended to use on a complex 3d model where I normally would have just "guessed" a cutter ball diameter to use. I was able to use a much larger cutter, and then check the backplot with the "Rest Robot" to see if there was still a few areas that might need cleanup, but the rendering simulation showed that it was okay. Of course, this permitted a larger stepover and less time on the machine. Oh, darn, that reminds me I forgot to charge the customer less because of this
