"Outputs" is not an option since each output is part of a whole. That means the total output doesn't change; the power only gets distributed differently between the groups.
I'm also bound by the industry nomenclature, which dictates "output", even though it may not be 100% correct.
Here's a bit more context:
The VS-570C offers three wireless TTL master modes, which are ABC, A:B, and A:B+C.
- In ABC mode, all three groups fire at the same power output.
- In A:B mode, only groups A and B fire, and power output for groups A and B is set at a ratio. For example, if the A:B ratio is set at 2:1, group A fires at twice the power of group B.
- In A:B+C mode, all three groups fire. As in A:B mode, power output for groups A and B is set at a ratio. Additionally, group C is the same power output as group B and is adjusted by EV. For example, if the A:B ratio is set at 2:1, and group C is set at -2 EV, group B will fire at 1/2 the power of group A, while group C will fire at 1/4 the power of group B. In this scenario, group C will be 1/8 the power of group A. For more information on EV, refer to Using Flash Exposure Compensation on page XX.