Mechanic never put car on the lift

I took my 2020 prius prime with 81,630 miles to my mechanic today for an oil change and a WS transmission fluid drain and fill. They have a window you can peek through to see all the cars on the lifts. They pulled my car up right outside of the garage behind one of the full lifts. I peeked through the window once in a while, maybe every 15 minutes or so. The car never moved. Then about 1.5-2 hours later they drove the car back around to the front of the shop and said it's ready. I responded, "but I didn't see the car go on the lift," with a confused look on my face. They said they jacked up the car and did the services. I responded, "But how do you know if the car is level?" They said they measured the amount of ATF they drained and it was 3.5 quarts, so they put 3.5 quarts back in. They said they do this all the time. When I peeked through the window each time, I never saw the hood of the car open.

Does this sound like a likely explanation to you? I never had a full view of the car, so I may not have realized it was on jack stands. Is it common for a shop to lift a car with a jack (and I assume jack stands) if all of their lifts are full with cars. It sounds reasonable to me, but I have never seen this before. I checked the engine oil on the dipstick and it was clean and at a good level. The problem is that I used less than 20 gallons of gas between now and the last oil change, so the oil looked just as clean before the change too. I can't tell, but the oil level may be slightly higher or the same as prior to the oil change. They used about ~ 4.6 quarts of oil on the previous oil change and the remaining 0.4 quart + 4 new quarts of oil on this change (assuming it was done).

I do not have any tools to lift the car or access the ATF fill hole and my 1 car garage is so small that I can barely get out of the car without dinging the door. Thus, I really don't want to check the ATF myself. Is this really something I should worry about? Am I just being paranoid?

 

Yes, the lifts were all tied up the whole time. They had 2 rows of 3 lifts and all 6 of them had cars on them the whole time. I did not pay attention if any of the lifts turned over.