I'm new to CNC lathes so go easy.

I've been setting up an old femco cnc lathe with a fanuc controller. All my tools seem to be traveling in the desired paths when I dry run a program. When facing a part, I am using Constant Surface Speed. However, when the machine goes to face the part, the spindle RPM's actually slow down instead of increase as the cutter approaches the center.

My guess is that the machine thinks the cutter has actually passed the Z axis and is slowing down??? I don't think it's in the programming. Could it be in the setup?

Any help or push in the right direction would be appreciated.