I might be missing something here... Back in the day when I did wet chemistry, the graduations on a beaker were really considered
approximate. For measurement of liquid, you used a graduated cylinder, burette, etc.
Now, if you have graduated beakers, the next question is what is the tolerance of the process? You may or may not pass either calibration or gage r&r with a beaker...unless your recipe tolerance is, lets say, +/- 100 ml. So, that may be an issue.
If your tolerance is wide enough that a beaker ends up being OK, I would calibrate that bad boy in house. Get it on your lab scope. Get a calibrated graduated cylinder and run with it. I assume you do not use a graduated cylinder already because it is a pain to clean, hard to handle or some other reason, right?
I don't do wet chemistry anymore. Didn't like doing the dishes.