Have you switched something to RF by chance, Just did a 7500 with a P.E. Palsma and receiver. The only duration I had to mess with was the volume ramping.

Sometimes I erase all the functions in a macro and start over when I am having problem and that has helped out. This was all the Pronto units, not specically the 7500.

When they are referring to the duration, double click a button, double click on the the learnt IR and you will see the duration adjustments, default or whatever you choose. I think I used .3 seconds for volume issues.