1525/1145 @ 905 for the 64, 1500/1145 @ 915 for the 56.
Haven't optimized them yet for this miner - these are settings from stak / cast, and i feel like they can do better now, at least maybe lower power.
EDIT: sorry, just realized OP asked for bittube (saber)... these are for cn7
I am guessing the voltage is higher than 910-915 and most likely that's consuming a lot more power for those extra 100 H/s.
Can you check the actual core voltage while mining using HWInfo64 tool.