Is it controlled (as in speed controlled) by the ecu?
I think the pressure regulator is passive with vacuum control?
Edit: WDS says so (pulse widh modulation) (still a vacuum pressure regulater is in place I think; there is a procedure with tools to check fuel pum[p pressure vs. pressure regulator pressure)
Control takes place via the diagnosis CAN, so maybe you can monitor it with inpa or progman (never seen it in inpa, but also never bothered to look
).
But I can't imagine the fuel pump not running @100% on WOT and +6500 revs.