When I pumped Gulf gas ($.329 NoNox), they were happy to get that and the windshield washed. No one ever specified which order to proceed in.Clearly, you never pumped gas for customers. 90+% ask you to check the oil BEFORE you you start pumping gas. And, you check the oil WHILE the tank is being filled with gas.
Required efficiency. Otherwise, other cars in the line (yes, there were lines) get pi**ed and start honking at you.