It is a great option to have PM burn the images across multiple disks and I like one can add other files (like copyright info or anything else) to one or all disks. But I find it would be great to let the user add directories the same way to one or all disks.
I like to add some contact part of my website (having folders in it) to all disks I burn for a customer, but I also like to add certain info directories to my archived DVD-s. The same to all disks if a collection spreads to more disks.
I hope you can and will add this feature some time soon.