Indeed if it only has 2 oz. too much you will probably be okay. The problem is that adding oil to a system is always guesswork. You really don't know how much has been lost.
The ONLY way you ever know is to flush totally, put in the right amount and recharge. This is rarely done unless the situation warrants it such as conversion or getting incorrect oil out of the system.
I'm still very worried if this is 2 oz. of Ester in a Mineral oil, R12 system.
Best of luck,