I have a very similar macro. If you dont want to use an addon to get bigger macros. Wrap that in a /click. This is what ive done. I have my macro like the following.

/startattack
/use 13
/use 14
/whatever its that turns of ui error and noise.
/click leftsideactionbarwhatever (where my long cast sequence paladin macro is)
/turn back on ui error and sound.