Sharp LT numbering

I acquired a little while back a Sharp PC-3000. I am very enamored of it and it's possibilities. Similar to the HP95 and will use the same memory card only with a more-manageable KB. In researching it I found it came out in 91/92 and was a follow-up to the Atari Portfolio. The UK company (DIP) that designed the Portfolio and this follow- up model, offered it to Atari, which had it's own problems at that time, who declined it and then Sharp snapped it up. Sellam gave info on a Sharp PC-5000 he was selling and Joe R. on a PC-7000. These model #'s make no sense at all as I believe both of these came out before the 3K. Anyone with any insight ? Or is it just that computer makers use no logical system for model #'s Lawrence lgwalker(a)mts.net bigwalk_ca(a)yahoo.com