'SPL' meters typically have large diameter mic elements. They also have 'A' & 'C' weighting and Slow/Fast response settings. And are stand alone calibrated measurement meters. Cal mics typically have small diameter mic elements. The amplification and frequency response correction is done farther down the line. I have not used cell-phone mics. But I see problems with polar patterns, with ability to exactly reposition the mic and to operate without people in the room. Thanks for the clarification and expansion. By the appearance of some spl meters I've seen thought it more likely similar sized mic elements..... My software has the various weightings as well as fast/slow response, tho. As well as a calibration file for my mic. For really high spl I'd get something meant for it, tho.
