My son has some fairly new Rottefella NNN bindings that were installed
where he purchased them. The heel plate makes a "swawking" sound when
he puts pressure on it (so, whenever he takes a step on the skis). It
looks like this is from the plate moving slightly up and down due to a
very thin gap between the binding and the ski. Is this normal for
this binding? Or does the binding (the heel plate) need to be
tightened? If it needs tightening, how is this done?

Thanks in advance for any help.

Rick H