A similar thing happened with the naming of the early
Macintosh models, in Macs that were based on the
Motorola 68030 processor.
Apple used the letter "x" to denote machines using the newer processor
technology. However, when they decided to release the Macinosh SE with a 68030, they named it the
Macintosh SE/30. Why? According to the
Macintosh Bible circa 1994...
"Apparently, Apple didn't think we could handle a machine called the Macintosh SEx..."