Thanks, as I'm reading more it looks like that 40dB shouldn't be a problem. The model above this one from the same company has 1.5dB accuracy and is a Type 2 meter, but is twice as much. We're not so concerned about accurately portraying the sound level relative to others' readings, but instead comparing between our own. So if all of our measurements are made using the same meter, and comparing noise levels above BG, do we need better than 2dB accuracy or will the results be repeatable and comparable?
EDIT It appears all the models below about $200 do not have built-in calibration. Is it worth getting a model with built-in calibration? These also tend to be the Level 2 models. Just not sure how worth it these will be over the $75 one