In smaller companies here in Aus it is not unusual to see SOPs change 'by stealth'. The regulator, CASA, is partly to blame for this. The regulations require all checklists to be approved and of course they charge vast sums of money to have their 'type expert' do this. Often the type expert has never flown the aircraft operationally, but will add layers of bull...t to the submission. I see checklists that tell you to fasten your seatbelt, switch on the lights, obtain a clearance etc etc.
So the way it is dealt with is you do whatever it takes to get the CASA 'tick' then get to work with subtle changes that you hope they never pick up on audit. It is rare that they do because the type expert gets promoted to yet another type he knows nothing about and you never see him again.
It's not a desirable situation, but for as long as they charge so much and fail to demonstrate a practical approach, it will go on.