Wow, that looks incredible!! I was always really hoping that STM could pull off an effect like this, but I never tried it myself!
._text will set the text value without automatically calling Rebuild(). Calling .text will automatically call Rebuild(), passing along the autoRead value. So I think it might have been getting the previous time wrong... what I meant was, where were you grabbing the "theMesh.Rebuild(readTime, true);"'s readTime value from? If it was theMesh.totalReadTime, the previous .text set call would have overwritten it