I'd wager that the second one is saying "I want to use 192.168.92.2, tough noogies if I can't get it" because its configured/provisioned for power sharing. The initial connection address for a newly setup HPWC is 192.168.92.1. The power sharing logic is driven by the leader, and it probably knows either "there are N slaves" or just scans 192.168.2.X where X is from 2 to 16 or whatever, or maybe even does a broadcast ping to 192.168.2.255 to see who responds. Another possibility, albeit much less likely, is that the leader actually doles out the slave's IP addresses on its own at boot time.
If you are then wondering "If the leader isn't doling out the IP's, how do the slaves get .2-.X" without stepping on each other." I'd wager that they get their IPs hardcoded during sharing setup and they are stored in NVRAM for restart. Even if that is not the case, there could be an algorithm during startup that says "Hey, is anyone on 192.168.2.2 ?" and if no one responds, it gets claimed. If someone responds, it tries .3 and so on. You'd obviously have to have some timing/delay stuff in there to avoid race conditions.