No. With a per-channel duty cycle implementation, all channels in the same subband are given their own (smaller) maximum duty cycle, not affected by activity on any of the other channels:
So for example, in a sub-band with 8 channels and a duty cycle of 1%, each channel has a duty cycle of 1/8% (that's 0.125%).
(In the image: if channel 1 is the only channel in the first sub-band, and channel 2 and 3 are the only channels in the second sub-band, and both sub-bands have the same maximum duty cycle, then both channel 2 and channel 3 will have to wait for at least 2 × 4 = 8 time units, because the second sub-band then has twice as many channels as the first sub-band. Or, if the second sub-band has, say, 8 channels, then each of channels 2 through 9 needs to wait for at least 8 × 4 = 32 units after sending. All regardless of any activity on any of the other channels.)