Understanding the macro process

I’m having difficult having spells cast as soon as they go off cooldown. So if I write what i believe is happening can you put me right please?

Writing a macro with sequence (1234) means
Key Press, pre macro, sequence, Key Release, post macro?

I have put a main cast in all 5 and still it doesn’t cast until the end of the loop (?post macro)

I have put loop 3 so I assume that’s initial, premacro, sequence x3, post macro, then back to beginning?

I need to keep frenzy on my pet at 3 stacks, so when i add a main spell it throws that off because of fine timing and delays I’ve added.

Added - I have now changed to time of the key press to 100ms, which help

Thanks for the info on mods…i’ll clear those key bindings and see how it works. Only Alt worked for me, and now that’s stopped.