Re: Starting at the beginning
When faced with your situation I agreed to take an 'equivalent' test, never got around to it, and eventually tested for higher rank with the new guys.
Yet I have a student who requested to start at the beginning and test rapidly as you suggested. He was more comfortable doing this, and we run through a lot of techniques in a test - so we are walking him through the ranks. I think either is a legitimate apporach. Your instructor makes the call, but he might be willing to run you through thte lower ranks if you think that works best for you - ask him.