Thanks for reading, Venerable. 
As always, translation may be the hardest part. I think in the initial question Vacchagotta actually does mean the present tense (“Is there no self?”). But the Buddha refuses to reply “yes” not just because of Vacchagotta’s potential confusion, but also natthi atta would also imply “there won’t be a self”, which in term would imply there currently is a self. I.e. the annihationist position.
How to translate that properly into English, I don’t know. Perhaps the present tense is actually best, because as I pointed out the English present tense can also mean the future: “There is no self [after death]”… But of course it kinda obscures the matter (if indeed my assumption is the case).
PS. I briefly alluded to the same point I made in a connected topic over here.