Hi,
Datasheet says:
* I_DAV --> current, diode, average
* bridge output current --> not input current
* rectangular --> not sine shaped
* d = 1/3 --> duty cycle = 33%
Now you need to know that if you want some output current, then always:
* two input phases out of three are involved
* two diodes out of six are involved
For the package power dissipation (that limits the average current) it makes no difference if always the same diodes are used or different diodes.
******
It even makes not much difference in power dissipation whether two diodes are involved or - the theoretical case - where three diodes are involved.
Klaus