Maybe before you try an extender, see if the DVD will turn on using the play button. If it does, you can modify your action a bit to use this to your advantage.

Once you know the "state" of the DVD, you can turn it off and it will go off, using the power button.

So, a macro might look like this, in the other action macros for other devices.

send IR Play
Delay .10 sec (may need to vary this)
send IR Power.

Then in your Watch DVD macro, send the Play IR command instead of the power command, to turn it on.

Dave