I have just taken the procedure to zero:
I open your file, I measure your hole, = 0.53mm, including in techdraw
I modify your hole to 0.525mm I measure it (by the two techniques) = 0.525mm, I save, I reopen, I measure = 0.53mm, Damned
I modify "Preferences" to 4 decimals places, I close Fc, I restart Fc, I redo all the tralala, and .... (roll of drums) .... the hole is to remain at 0.5250mm ...... youpie
it should be written on Fc's pediment:
"DO NOT FORGET TO CLOSE Fc FOR CHANGES OF PREFERENCE TO BE TAKEN INTO ACCOUNT"