Empress--given that nobody here has received a reply, regardless of the address, I'd say that it doesn't matter much. I guess you could send to both addresses with a PS indicating that your letter was also sent to the other address. Not that I think there's too much danger of your getting 2 responses.
One way to increase the probability of a CEO-addressed letter landing on the CEO's desk is to handwrite the address and mark it "Personal and Confidential". Maybe a little scent on the envelope!!
Personally, I would guess that there's such a massive screen between RM and us poor travellers that there's zero chance of his ever seeing the letter even if finds its way to somewhere near its destination.(Although if yours isn't a letter of complaint, that might be such a rare event that it is presented to him with a flourish of trumpets and delivered on a silver salver. )
If you do get a reply, do let us know; it's now months since I sent the first letter, and sending to RM has obviously been a waste of time for me.