Hello experienced people, I'm retuning a Wheatstone English from old 'high' pitch to A440 and its all going reasonably well. I notice though that every time I file metal from the base 1/3 or so, no matter how little, the tongue always ends up inside the housing and needs to be bent out in order to get it back to the 'speaking' position. Im putting a feeler gauge under it while filing. Initially I thought this is the friction of the file warming up the outside of the reed and causing it to expand but it never recovers to the original place once its cooled down. Is this a fact of life I wonder.