Thanks for the info Randy,
I may just go for the R40 and return the mx-450.

On the mx-450 the pause trick as the first step of the macro does not work on the
physical buttons, it sends the original command and then if you hold it for whatever the pause was set to, it executes the macro.
If the pause trick works on the physical buttons of whatever device you are in that would be idea, as then I could have the channel up and down also work as the page up/down if held for a second.