I've used replenished developers since the late 60's, there's major advantages in using Xtol replenished, one of which is economy.
The Kodak replenishment figure of 70ml per 35mm film or 80 sq inches are quite high, this is based on bleed replenishment, and in practice is more than is theoretically needed. So the figures above are meaningless particularly when processing 120 and 5x4 and multple rolls of 35mm.
However the other advantages are finer grain, better acutance and an improved tonal range and very consistent results, plus you have developer made up ready for instant use which cuts times considerably. It's forgotten than many developers were designed for replenishment from the outset and their use dilute came later.