[Panther]

For an f10 Bj 2012 550i

Do you want to have everything on the silver plate, or are you also able to try it yourself like others do? If you have no basic knowledge of flashing, you should generally leave it alone or acquire the knowledge on your own car. But it looks like you're not doing it on your own vehicle, but on other people's vehicles.
And if something goes wrong, are you asking for help? And the customer drinks coffee and waits until you fix it?