Maybe we are reading different papers or something. Both studies that I linked more or less talk about the same thing - intergenerational economic mobility as evidenced by income plasticity in one or another form (another, a more comprehensive study can be found here: https://inequality.stanford.edu/sites/default/files/Pathways-SOTU-2016-Economic-Mobility-3.pdf). There is nothing in these studies (at least that I can see) that looks at the intra-generational mobility.
Yeah it was there. I read it. LOL. I can't copy and paste from the document unfortunately. But it is mentioned.
I only had a cursory look, so I would not be surprised if I missed something.