I addressed the quote. You singled out time, but there are two variables. At lower RPM you have lower pressure, and more time. At higher RPM, you have higher pressure, and less time. Total leakage per rev could be identical in those two scenarios, but the only way to know would be testing the exact configurations over the operating range. For your theory to be an absolute, the pressure would have to be constant....we don't know that it is. You simply can't make an accurate blanket statement that less time equals less leakage.
The relief pressure comment was when I said that minutia such as internal leakage doesn't matter in the real world....the pump typically puts out full pressure, and volume, before WOT, so delivery per revolution isn't always higher at higher RPM settings. So, there isn't necessarily a need to run at WOT.
