Actually when my son started doing this it was a big relief. It was when he finally understood that I can't read his mind, and he can't make assumptions reliably about what I mean, even though I try my best to be very specific. The more specific I am, and the more questions I answer, the better he gets at predicting and the more confidence he has in his abilities, the less questions I get. There is light at the end of the tunnel.
I also generally add something like "barring unforeseen circumstances or emergencies, so he knows I am not lying when I say I will do something and it doesn't work out. I do not disagree with BuyerBeware, mind you, I just need to reinforce that &*?% happens. I will also sometimes tell him he may need to remind me, as there are times where I forget things.
It is a work in progress. 