B757-3: effect of wing anti ice on maneuver margins

[is7]

Hi,
Boeing states (FCTM) that on the B757-3 the use of wing thermal anti ice reduces the maneuver margins. I have been looking for an explanation on this for a while, but have not been successful so far.
My basic idea: if WAI is used it is assumed that ice/snow deposits will remain somewhere aft of the leading edges, which will negatively affect the aerodynamic of the wing and therefore reduce the maneuver margin.
Any comments or references to this topic!?
Thank you!

[aviatorhi]

Heating the wings doesn't effect your "real" maneuvering speed (ie. what the aircraft is capable of due to the laws of physics).

What Boeing have done is any time you lose an engine, turn on WAI/EAI (depending on the frame, some don't "bleed" enough for EAI for it to be a factor), extend or retract the gear or flap, etc. is program the "maneuver margin to stick shaker" to increase/decrease as is appropriate to provide more warning to the crew of impending stall. More warning is provided due to the degraded performance of the aircraft with gear/flaps down and WAI/EAI on.