Then he should stop selling them at 4pm so you don't waste your time. Or better yet, stop selling them at 5 and let the elixir end at 6. But yes, I see that now. An annoying design flaw to say the least.
Personally I don't mind the limitations, but I'v already enjoyed all the MC "RP" I can tolerate and I've just happened to have logged in the past two times right around nightfall.