on the URC forums it was said that recently purchased MX980s only need a .1 second delay between macro commands.   i haven't tested this out yet since .5 seconds between steps don't really bother me and i know it will work.

In my experience it is only necessary to put in .5 second delays if you are sending commands to different devices in the same macros.  favorite channel macros for instance ,don't need a .5 second delay.