Tomi,FD on a physical level means anticipatory tension; tension that arises automatically, BEFORE a specific movement is carried out (sometimes triggered even by the mere thought of it). Because of this you need to break this automatism by re-instructing your brain slowly, consciously and repeatedly so that it doesn't REACT (badly) but ACTS (correctly). I would say anything that helps you break this circle of "intent to play - reacting with tension" will do you good.
To me the exercise I suggested you seems logical and works: first learn to release unwanted tension by listening closely and using just enough pressure, then repeat, repeat, repeat... (no tempo here, be very slow). Learn to associate playing with ease of movement first, then - later - let your fingers do the work without too much attention ( = letting go).
