Purchased movies and TV Shows keep reloading even when on device.

When I have both the SD and HD versions of purchased material from Apple, the SD files always, always reload onto the device even when they are already on it. When I delete both versions of files and download just one or the other, the files do not reload when they are on the device. How do you people keep files from reloading onto a device when they are already on it and still keep both versions of the files in media folder. Using just HD wastes up to 50GB of space on iPad, and reloading all the files on my iPad when I plug my device in can take 45 minutes to an hour. Been a problem for a while. Using iPad Air 2, and latest iTunes. Has been a problem on all previous iTunes versions for a while. It has to do with both files being in the same folder in media folder. iTunes will always reload the SD even when it is already loaded.

I have tried unchecking the TV and Movie syncing options and restarting my iPad. It does not work.