SOP's on everything vary between carriers I'm afraid which can seem very confusing to the pax who might have some interest in these.
This is probably true for those who do not fly much, but frequent travellers will quickly learn the different ways that things are done on different airlines.
Most of my clients have different business procedures, often the only time they are aligned is when they refer to using a standard computer software application such as SAP, because it has standard procedures and that is the same as an airline using the Boeing checklist.
What is really confusing to pax is when what should be universal processes differ, such as security.
I note that Jetset lady cannot use a DFT approved washbag at MAN.
Now that sort of thing gets confusing.