Is delay allowed?

[Sservis]

I'm wondering if I can do this on a single key press:

keydown (Master):

/startattack
/cast Spell

keyup (Slaves):

/assist Master
/cast Heroic Strike
USE IWT hotkey

Is this allowed and is this how ISBoxer does this? IWT + Cast is done at the same time? I couldn't find anything in the docs: http://isboxer.com/wiki/WoW:Interact_with_Target

EDIT: Specifically I want to know if the key-up action you can see up here is OK (or do I need to separate the IWT from it).

I would expect this to be fine the triggering of the actions to be fine. For what you're doing on the trigger, the question to ask is "Could I write an in game macro (or addon) that does that?"