you dont show any evidence of poor technique.
you are being told a load of nonsense.
have some confidence there boy.
during my training a bazillion years ago now I had an instructor that insisted on low approaches to the runway ...to the point where I had to power on to climb up over the boundary fence on each approach and let down to the touchdown.
nobody could understand his take on the training and so he was awarded the DCM.
(dont come monday, you're sacked).
your guy seems to have developed a similar oddity.
focus away in the distance to judge height and use your peripheral vision to judge position. thats the way you do it.
if your landings are gentle things then you are doing it correctly.
if you keep on banging it on then he may be trying to give you a clue as to how to remedy a fault. ...but it seems an odd suggestion to put your head on the window.