The stock 971 Renthal bar is 99mm tall, the Carmicheal bend Pro Tapers, (like the ones on your big brother's bike

) are 77mm tall. So the Carmichael bend ends up being a whole 3mm taller than the stock setup when put on a Sub Mount. (+25mm for sub mount, -22mm for carmichael bend = +3mm total)
I think the RM low bar like Ken used on the CRF's Only bike are 74mm tall and thus end up being exactly the same as stock height.