Just to echo what fantom said. 50' might be a tad high. 30 is a good ballpark figure.
Also, as has been pointed out, "RETARD" is not a command, but an advisory. Waiting until you hear that command will ensure a longer than necessary landing. My technique is at 30' you check the descent rate, slight pitch change then take off a know width of power. If all is fine, no excessive sink, then the power comes smoothly to idle.
Try some manual thrust landings. Remember the throttle position when you take the active and stand the power up, either CFM or V2500, the thrust lever position for checking the stable spoolup is also the same positon config full on the glide slope.