Per the title, the Orb Master node says it gives +30% cooldown recovery per point while it’s actually giving only 20% per point.
If it gives 30% cooldown, then 1 point should give Devouring Orb a cooldown of 4s * 1/(1+30%) = 3.1 seconds. However as it’s only giving 20% you get a cooldown of 3.3s which may not sound like much of a difference, however it does change the breakpoints for the max number of Devouring Orbs you can have out at any one time (echos notwithstanding). If it gave 30% per point you could have a max of 7 DO at once, while with only 20% you can only get 6 DO out at once.