I think somewhere in this long post there is mention of blending up the PT with a blender or immersion blender to make it nicer to apply. Absolutely no negative effects from doing that.
If a PT doesn't last, it could be because you need more. Or it could be because of a lot of conditioner used to "re-soften" the hair post-PT. People talk about "protein vs. moisture" but considering the actual effects of the stuff we put on our hair to condition, I think "protein vs. softness" is more accurate. Protein can leave a dry, tangly, rough feel. I usually use only enough conditioner to help detangle or else the PT is less obvious. Protein also conditions and is a humectant. But absolutely NO slip!
Protein bonds to your hair, but it will come off. So repeating the PT is okay. I can do them often if I'm that motivated. You eventually find your "point of diminishing returns" with them.
I use conditioner with protein and it seems I can go longer between PTs that way.