I don't think that this is necessarily true. I've done IAgirl's PT and left it on for only 5 minutes to very good results. We've had this discussion before. You pointed out that according to Natural Haven, there is aDsorption and not as much if any absorption in a PT that isn't left on very long. This may be true, but the aDsorption may still be helping her, as it helps me as well and others.
When I do coconut DTs on the other hand, the effect lasts for a long time, as it should because according to multiple posts you've written, it can really penetrate the shaft which makes it such a wonderful ingredient. It makes more sense to me that her hair is getting frizzy in between PTs and not coconut oil DTs. It is much easier to lose protein (especially aDsorbed protein) than it is to lose the effects of coconut oil. The effects of a coconut oil DT should definitely last longer than 5 days. Proteins on the other hand can wash out with each cleansing session.
With that in mind alslgirl, I would also try doing the heated version of the gelatin PT, keep it in for longer so it can properly aBsorb, see if that helps.
If you get the Colorful Neutral Protein Filler and put it in a leave-in as well that should help as it will definitely have time to absorb.
I do agree with you, Firefox, that she may be better off backing off the shea butter. My RO is very different from my SM LI; that's probably why the combination works me. I get moisture from my RO and seal it with my shea-buttery LI, and that works for me in high-dews (conditioner-only styling).
As it stands alslgirl, your hair's diet may not be varied enough. Hope this helps!