New to game

[worldofneil]

But once you place the target specifier in the macro line, like <t>, <tt>, <mo> or whatever, then that's the only target that that line of the macro will use.

Sorry, but no... (just try it!)

Damage spells and actions do work exactly as you described, but healing actions are different. If you try and cast a healing spell on a mob, regardless of the method, if always casts on yourself (if it's a spell that you can cast on yourself normally).

So if the first line of the macro is using <t> it'll just cast on yourself causing the others to fail.