So a lot of the threads about this are somewhat dead, and I would rather not raise one in case no one is looking, So I will start my discussion here.
A lot of powers like Arcane Surge, pre-FAQed Wild Arcana and the like say "As a swift action, expend one use of mythic power to (do something):
A lot of people read that that means that you can (do something) as a swift action or a non-action, that it is part of the swift. But mulling it over and looking at it, it really seems to say: spend mythic as a swift, do something as normal action.
For instance,Arcane Surge says: As a swift action, you can expend one use of mythic power to cast any one arcane spell without expending a prepared spell or spell slot.
This means, you spend the swift action and cast spell normally, except that you do not loose it as a prepared spell or loose a spell slot.
If that is the proper reading, then Inspired Spell should be the power that is FAQed or Errata-ed, since by its reading, spending the mythic is a non-action.
I agree with your interpretation of the pre-FAQ but there's nothing we can do now. As for Inspired Spell it's a standard action too.
Inspired Spell (Su): As a standard action, you can expend one use of mythic power to cast any one divine spell without expending a prepared spell or spell slot.....