I am going to try to explain it the way I saw it.
I have seen this in a video about configuring cisco switch for Cisco USC fabric Interconnect. the steps were:
1- they have configured 2 interfaces as trunk ports
2- they configured the trunk ports with portfast
3-they have configured the 2 interfaces that are trunk ports as etherchannel group 10 (po10)
4-then they configured the etherchanel port as a trunk with dot1q encapsulation.
5- they configured po10 with portfast
I wonder if step 2 is necessary, since portfast applies only to access ports ?
I wonder if step 4 is necessary, since po10 is based on the existing trunk that was already dot1q encapsulated
I wonder if step 5 is necessary ,since po10 does not need to be portfast.
Any clarifications will help.