Let me give you something to ponder.
As an instructor you still use the same suit as you did during AOW? Do you really think the suit has the same positive buoyancy now as it did way back then? Over time a suit does not retain it's original thickness or buoyancy characteristics.
Your profile is pretty thin but hopefully you have done a few hundred dives since AOW so part of the drop in lead is a drop in positive buoyancy of your now 5.75/5.75 2XL.
