Car codes and numbers....

Over on the 2G Yahoo Group there's been some discussion on how to deal with the changing of the numeric coding with the '05 Prius packages.

For those who don't know what I mean:
For the '04 Model Year Prius the BC (highest) package was also package #9
for '05 that exact same package--BC--is now #6 due to a decrease in the number/types of options packages being made available.

Although using only the alpha code would be the single most accurate way to describe one's vehicle, it's also the most confusing b/c BC doesn't mean much, no one can remember what's in the AM vs the BI package. That said, most of us can't remember exactly what's in an '04 #3 vs an '04 #5 either...but we know, intuitively, that there's more "stuff" in the #5 than the #3...but that won't, necessarily, be so across the model years. (i.e. an '05 #6 will have more "stuff" than an '04 #8)

The option proposed there that seems best to me, so far, is an, appropriately enough, hybrid version of all these. Each of us would describe our car by year, alpha code and numeric code for the year made!

Example:
05GY1
05AG2
05BI3
05AM4
05AI5
05BC6

I've changed my signature to coincide with this format. I'd like feedback if everyone things this will work here and is the best way to do it or if there are other/better options I haven't considered.