Vilas, don't forget that 'F' and 'S' speeds are the MINIMUM speeds that flap should be retracted at. With a positive speed trend there is nothing wrong with retracting at S+10 knots - you're giving yourself a buffer and when you move the lever you're going to be almost at GD speed. This is not so critical on lower weight departures but at higher weight takeoffs the cleanup needs to be more "efficient" in terms if energy maintenance and using speed TREND effectively.
Alpha lock will only prevent the SLATS from retracting if the AoA is greater than the limit
at the moment the lever is moved. Once the SLATS are retracting the will keep going. So only select FLAP 0 with a nice positive speed trend and a buffer - if hand flying it is easy to "adjust" the speed trend line with sidestick to prevent an overspeed - it's called aviating
To clarify my earlier post, selecting say 225-228 knots is a momentary "fix" whilst the last few seconds of SLAT retraction occur - your hand wouldn't even come off the FCU SPD knob. Thrust will not reduce because you will be in THR CLB and as soon as you're clean, PUSH for MANAGED speed the attitude will reduce to facilitate acceleration to 250knots / climb speed.
@gAMbl3 - because at very high weights you could end being clean well below GD. Additionally the pitch to maintain 215 may well put you above the AoA threshold for Alpha Lock in turbulent conditions. Keep the energy/speed/trend positive, watch the SLATS as they retract on the E/WD, intervene / manage as required.......it's what we're paid to do.....fly the aircraft safely within its limits.