There are two components to your questions; the logical and the emotional.
Logical issue:
There is no reason not to go back to dinos; won't hurt anything in the slightest.
Emotional issue:
The underlying question is "why give this gift" of free oil changes? Are you doing it because it's of value and you like the person? Or, do you percieve the gift to be of no value, and it's an easy out to the gift-giving sequence?
With today's rising costs of lubricants, I'd say they're actually worth something. On the other hand, where is the serivce to be done? Is the risk of poor service outweighed by the value of the oil change?
Shouldn't you really be asking Dr. Phil these philosophical questions????????