Classic HC - Light of Elune Macro BUG!

So I use a simple macro to use Light of Elune and Hearthstone to bubble hearth. I click the macro as oppose to keybind it. It bugged out. I suspect that it used the potion (Light of Elune) on the “down click” and it started hearthing on the “let go” of the click. So they didn’t line up 100% and the bubble (from Light of Elune) from the potion ended slightly before my Hearthstone finished casting. I’m sure everyone knows that Light of Elune provides a bubble similar to Divine Shield that lasts 10 sec and Hearthstone is a 10 sec cast. So we have just enough time with these two items to “bubble hearth.”

/use Light of Elune
/use Hearthstone

So my questions are:

  1. is there something wrong with the macro?
  2. I heard other players talking about some UI option that would execute all “clicks” on the “down click” as opposed to the “let go” - but I can’t find that option anywhere. Could I enable it with a console command?