going from synthetic to regular motor oil will eat up your seals and you'll blow your motor up. trust me i watched my cousin do that. bad idea lol

 

No.

 

Yes you can, although you wont actually hit the recomended time/mileage when you do it.

Although, you could just get the services done every 4.8 months, then you would get all of the comp services... but honestly whats the point? Just to get the extra one in? Not really necessary if your only getting them done every 6 months anyway...