Mfr was just an abbreviation for manufacturer. If you contact the company who makes the instrument (OEM) they should be able to supply you with a suggested calibration interval.
As supplied simply refers to the readings you obtain when you calibrate an item (prior to making any adjustments).
Cal. is just an abbreviation for calibration.
As you are new to MSA and possibly calibration? You may want to forego anything overly complicated until you can obtain further training. I would try to find out if there are any requirements for your specific industry regardingi these devices...if there are no specific interval requirements I would suggest following the manufacturers recommended calibration interval.
If you get the devices calibrated by an outside calibration laboratory ISO 17025 these folks may be able to suggest a reliable calibration interval which will provide you with acceptable confidence. Don't be afraid to utilize their expertise either, if you have questions about the calibrations, intervals, msa studies, get on the phone with them and see if they can assist you, most would be more than happy to provide you with the information you need.