Not to my understanding-with the mast butt max forward and headstay at class max (rig tune slack) my mast sits hard against the back of the partners, and my headstay is completely loose. So on my boat at least, the fulcrum is where the mast passes through the deck.
But-I think my numbers are off. I did the calc's a long time ago. I think the rig moves fore and aft at the hounds about 8" for every inch of movement on the cabin floor (sorry for the exxageration-I'm not an engineer). Still a significant difference though , as rig tension settings and headstay sag are dramatically impacted by fore and aft position of the hounds.
I know this from experience-my mast butt was frozen about 1 1/2" aft of the class measured position for the first several years that I had the boat. My rig had HUGE prebend and my boat was slow until I fixed the butt position (with a lot of effort) during the off season several years ago.
