You can actually achieve this with the Detune knob setting it to +9/-9
DETUNE – [DETUNE] : Controls both detune amounts for the left and right channels. Range is +/- 40 cents. Left and right channels get opposing amounts of detune (for example -30L/+30R). For enhanced versatility, the channels can be set with different opposing amounts. Left channel is the base detune amount and right channel can be adjusted around an 8 cent opposing window (for example -16L/+12R to -16L/+19R).