Rife used a plasma tube which is a very powerful way to apply frequencies. After killing a great amount of pathogens, the body needs time to tidy up, to detox. The contact mode is much weaker and the remote is even weaker. So with remote it may be justified to keep on killing continuously. However, detoxing is suggested as part of the repeating program, or on a different remote. And natural detoxing, like spirulina, chlorella, chitosan, good nutrition and much water is also suggested.
So I guess Rife didn't do long treatments to not to overtoxify the patients. Remote is way less intense, so equally less toxins are generated.
For more details, please check the link: