I once read that a famous organist/composer (possibly William Boyce?) overheard a colleague criticising another player's fingering and responded "What would it matter if he ran his nose along the keyboard as long as he made a pleasing noise?" Play in an "authentic" style if you like (or if your teacher insists) but there are other legitimate styles of playing and for my own part I am delighted to see an organist not in thrall to the authenticity fascists.