Service parts at Stealership



So I call up my local dealership and ask for pricing on oil, filter and plugs for now and a service B estimate cost.
I was informed that service B would cost me R5600 and that's just oil and filter change and inspection from front to rear.

I called up the parts department and filter will cost me R282, Air filter is R907 but I dono if that's both or one however I assume its for two. The 16 plugs will cost me R1476. Here is the surprising part, I query the oil being 0W40 Mobil 1 which I see is recommended and they tell me no the car has to be booked in for service to get that oil as they don't sell it over the counter however I can obtain Mobil1 5W30 oil over the counter

anyway oil filter oem is always compulsory in my books, the rest I will see around at the spare shops. Would it be a good idea to change the tranny filter as well as the oil now at service B considering the car has 230 XXX km's?
Thanks in advance


