It depends on the time of year you are going and if it's an EMH night.
If there are two showings you can just go to the second show instead of doing the package.
I've done Fantasmic with and without the package during Aug, Sept, Oct, Nov and Dec and felt it wasn't necessary any of those times of year.
Please note, that the package seats are guaranteed (up till 30 minutes before, then they can and sometimes are opened up to all guests), not preferred seats.
I've gone and found a great seat at one hour before to 45 minutes before with better seats than the package seats.
I would do the package if it were an EMH night, a very busy time of year or a time of year that I don't know a whole lot about. I don't know a whole lot about April. I wouldn't do the package though if there were two showings; I'd just go to the second one.