That's what I would recommend, taking the gravity is one of the last things I do before actually transferring to a fermentor.
Upon doing a little research, hydrometers are either calibrated for 68 or 60 degrees (F).
It seems like yours is calibrated for 60 degrees. By using the numbers you mentioned and if it was post mash pre boil I imagine the temperature then would have been between 150-160 degrees. So if you type that in for the temp, along with your actually gravity (1.034) you'll notice that in reality your gravity was exactly around what it should have been (1.050-1.055). : )