That's an interesting question. Looking at the documentation the NPN card (CHWW) and the PNP card (CGWW) have different switching characteristics (NPN is faster

That's an interesting question. Looking at the documentation the NPN card (CHWW) and the PNP card (CGWW) have different switching characteristics (NPN is faster on and slower off). But I haven't noticed any difference in usage patterns.