You really can't rely on that Mic for anything other then the SMS, as they likely did a batch build of the mic and used a calibration file in the firmware of the SMS. Not knowing how far off it measures and being unable to correct for it is not going to help you all that much...
I posted in your other thread about sub tools....
I'll be getting one of those Dayton OmniMic systems for myself, its a simple all in one package, but $300 to the normal user - will probably steer some people away. For what I have invested, it'll be a nice simple tool for me....
Not sure if it'll be worth it for you as the same price as the sub you just bought....