Is ISF calibration only possible on panels that state they can be calibrated, such as the Pio plasma's or can any panel, i.e. the Sharp Aquos, benefit by a visit from an ISF expert?
The benefit of ISF calibration is model specific based on how much flexibilty the menus have. Almost every model on the market can have the core parts of a calibration applied to it. Those products that have the ISFccc logo have additional memories that can be locked by the calibrator to preserve the calibration.
The Pioneers add an extra layer that allows the calibrator to communicate directly with the panel software to do some extra tweaks over and above that in the user menu.