I expect Shockwave to be taller than the Autobot cars, because the original size-chart for Gen1 had Shockwave just at Optimus's shoulder height...
http://www.toycollectors.com.au/botcon/bc05/d38.jpg
I think Hotrod might be a little taller than the Autobot cars, but probably not more than a head taller. (being in front of them in the display case and next to a tall toy can have a bit of an optical illusion effect)
Thanks for that.
I was just coming back to post that someone on TFW had replied to my query, saying that it translates to Defence Commander... which might have been his Japanese toy function (the Hasbro toy had Military Operations Commander*).
(*sometimes it scares me how odd technical details from toys that were released about 30 years ago are still stick in my head... and yet I rarely got better than Cs at school :o )