I think that some of the X1 boxes are sensitive to the rate that codes are delivered.

I had a recent experience with an Arris X1 box after converting an iPad to iOS 8. iOS 8 is a little faster at IP communication and my channel selection codes were arriving too fast. I also ran into some out of order command execution issues, but this is probably not the X1's fault.

If you are having issues when sending multiple commands in a macro, add some delay between commands.

On the Arris X1 I noticed that I should delay commands long enough for a channel change digit to be acknowledged on screen before sending the next digit. I can imagine that the optimum delay would also be dependent on the mount of partial string search data that is displayed. Sending a digit while the search result is being populated is probably a bad idea. (but I have no proof of this)