The K5 and PW1 are i.MX50 and newer are i.MX6
The PW1 has been brought into the realm of 5.6.x series, but not the K5.
It can't be the scanner, the KT-2 uses the same IR scanner and it runs a 5.6.x firmware.
For awhile, the PW-1 and the PW-3 both ran 5.6.1.1 - different SoC devices - Duh.
So I'll agree -
Our Nicknaming conventions aren't any more messed up than Amazon/Lab126's numbering conventions.