No. It's barely measurable and it happens all the time. AC systems use a schrader valve that has threads and it is impossible not to have any lost when servicing. If you look on the name plate of the compressor unit it may take 19 lbs or so of refrigerant, an ounce or two won't make a difference.
This weeks weather is extremely humid and over 90 degrees everyday. High humidity takes more energy to cool the air because the house humidity also goes up. If you have a thermometer that tech use with a long needle like probe, it gets poked into the fiberglass ductwork just above the air handler. It should read between 10-15 degrees cooler than the incoming air. It is a little test that you can do. But if the tech had gauges on it and he didn't need to add refrigerant, the coils and filter are clean, your system is good. If it needed refrigerant he would have mentioned it since it is a money maker for AC service companies. If it is a R22 refrigerant, outlawed, you'll need to remortgage the house, R410a, it is the standard and affordable.
