Be careful! When your opponent is about to attack from the rearcourt, a little bit higher than the net may be ok, but if the attack is average, or you are in other situations at the net, having your racket higher than the tape can be detrimental. I am imagining a scenario where your partner plays a drop shot and your opponent comes forward to the net to play a net shot. If the net shot is reasonable, you risk hitting the shuttle into the tape. If your racket starts at just below the level of the tape, you racket can rise up and into the shot, with less fear of hitting downwards unintentionally.
I am not saying the advice by coach LJB is wrong - it is a good starting point. However, I am issuing caution. There are times when having the racket head above the tape makes a shot more difficult, if the opponents shot is of a high quality.