Problem of priority in the macro

I’m trying to do a macro with two spells. One generating a resource and the other spending it. Using the step function (priority list 112123…) with the macro:
/cast [nochanneling] Eye Beam
/cast [nochanneling] Eye Beam
/cast [nochanneling] Demon’s Bite

But very often Demon’s Bite is done in a loop without using the spell with a higher priority(Eye Beam). Do you have a better method for short macros like this?