Ampacity of single conductor cable in cable tray

[lakesailer]

In our application we are running 3 parallel runs of (phase A,B,C, and Gnd) for the power to a 700hp VFD. Am I correct that if we space the groups of 4 cables each, apart from each other by the 2.15 times the cable O.D., that we can use NEC table 310.20 to determine the ampacity for the phase conductors? When the groups of 4 cables each leave the cable tray, each group will route through an individual 18 inch long conduit/nipple into the top of the VFD cabinet.