Same here re: the U moving to the LOS. Unfortunately it has become much tougher over the past couple of years with all of the quick slants and short crosses. I also now have schools that have a route for the TE that is to go wherever the U is. As I move, they move. I know this because I've not only experienced it, but I've asked the TE about it.
There is a movement and discussion to possibly move the U behind the LOS to the A side of the ball. I'm not in favor of it, but it looks like it will probably happen.
But going to the OP, our mechanic is for the U to be secondary to the R. I work very hard to know the LOS on every play for this reason as well as IE downfield calls.