Refrigerants have R DESIGNATIONS...
When I say BLEND ( or the EPA calls something a BLEND)... it means more than one of those are put together..
FREEZE12 is 134a PLUS one of the R400's.

What it means in a practical sense is that since AC shops are typically set up for EITHER R12 OR R134a ...
and are very careful about mixing refrigerants in there equipment due to the different oils used ...and other considerations..

You are not likely to find a shop who will service your BLEND equipted system...

Don't take my word on this... call around your local area saying you have FREEZE12 in your system and need it topped off or checked or serviced...

this is in addition to having to load in the liquid state ( which if the valve on the downside of your compressor is faulty can break reed valves just like mistakenly putting liquid into the suction side, having to worry that leaks will allow only the lightest element out ( which may be the better oil carrying one ).. , and there is the oil miscibility question .. which everyone agrees is not a problem with R12...