You must replace pan every time the bottom drain is opened. Or else it will leak, not to mention that the drain strips very easily. The pan has the filter in it, so again, it must be replaced at a service.
Not sure where Bentley gets their info, but that is wrong. With the original BMW instructions easily available online, I wouldn't go anywhere near that book, but that's just me.
https://www.newtis.info/tisv2/a/en/
When changing the pan, be aware that there is a specific torquing pattern and procedure.