Hello!
Basically, when you use, say; /macroicon "Fire" it will basically replace your macro image with that of the actual ability/spell that is specified. It also displays the mp/tp cost, will be grey if not enough mp/tp to use, shows recast time, displays a checkered line around the icon to indicate a "combo" can be made.

The problem/bug.
It will not factor in Astral/Umbral charges from thaumaturge. So the display will read the incorrect mp cost.

An example.
If a Fire spell costs 72MP, and i gain Astral Fire, it will cost 144MP but will display 72MP. Also if i have under 114MP but higher than 72MP and have Astral Fire on, it will not be grey as if i did have MP, it will stay lit up, while telling me i only need 72Mp to cast.