if you could get the original footage before it was deinterlaced, it would be slightly
higher quality as the dvd will pass-through the interlacing as a bob-weave in the playback device.
if you right click always deinterlace if its progressive, it will lose quality.(if it was interlaced, you lose quality here as it isn’t passed through into an interlaced sequence)
in interpret footage section, if its set to interlaced when in fact, its progressive,
it will lose quality.(if it was interlaced and you set to progressive, you lose quality here as it isn’t passed through
finaly,
put all your footage into an interlaced lower field timeline. then export ntsc lower field interlaced mpeg2 dvd compliant.