Yes pushing two buttons one after the other "shouldn't" cause too much problem BUT the facts of the matter are that the PF and PM were distracted enough turning on Packs after T/O directly casing premature Flap retractions.............
Mainly on the A340 at heavy weights I might add.
The ergonomics of the IAS display on the PFD also didn't help with the S speed "off the scale" above.
Either way, since changing the proceedure there has been a huge reduction in these events.....
Read it how you will.
