100% scam IMO... think about it in any other business, profession or setting...
You take your car in for an oil change, agree with the shop that it will be $80 all in for the oil, change, filter, etc. Once they get your car on the lift and drain the oil, they tell you that the oil is going to cost you an extra $60. Yes the exact same oil that was included when you booked and paid for the service. Well now you're stuck, your car is on the lift with no oil in it, and they're pretty much cornering you into paying an extra $60 for something that was already included knowing that you have few options to get out of it... scam.