The way I understand hydraulics is if you have pressure even if it is supplied to each end of the pipe as long as there is an area of lesser pressure in the system there will be flow to that area of lesser pressure.
That's correct. You can have pressure and no flow, and we have remember that these engines are over pumped. Well most of them are anyway and probably should be. At low engine speeds with a big pump and not much oiling moving through the engine you can have pressure and no flow.
If you want me to tell you the crossover is some magic bullet I won't because its not.
All it will do is move oil from the passenger side to the drivers side lifter bank. 99.9% of the guys I know who have done it still feed oil up from the number 1 main. It can't slow the oil down to make the turn or any other of the garbage that's been published about it. It has never saved a single bearing because it can't.