Barbiegirl wrote :
"noit true. flight code for scheduled is ZB and for charter it's MON , it states the flight codes on your roster so you know what you will be operating."
If you worked one season perhaps you were lucky, but in fact it often happens that the flight you will operate is changed while you are driving to work or after you have reported so qwerty was right in that respect and indeed in everything else he said.
The crew operate both types of service to a very high personal standard so it makes precious little difference really.