I will try using an MCE profile and report back.
Indeed, you can´t change that setting on the Harmony 300i.
I can´t say it doesn´t work. It does, but after having used a remote which is buttery smooth, you do
notice the difference, like going from a 2.x to a JellyBean (4.1) Android ROM.
I like the Harmony but unless I can make it work as smooth as the remote bundled with the tuner,
I know I won´t use it.
Concerning Jason´s post describing how Flirc is coded, I know in LIRC you can configure the gap
between button presses. Once configured you don´t have this sort of problem. That is, it is something
which has already been done within LIRC; it can be adjusted to work reliably with quite different remotes.
I´d love to help him getting it right, but the code within Flirc´s firmware is closed, so only he can do it.