[2021] Matchmaker Mismatching!

Matchmaking allows for a spread across 3 tiers at the most. This is referred as "+2/-2" because a Tier 6 could see a Tier 8, or vice versa.

Being bottom tier or top tier is perfectly normal, and you can learn more about the how the Matchmaker works in this How It Works video:

Video Link: https://www.youtube.com/watch?v=r7PmOMVLgsE

The change being referred to is a limitation of 3 Battleships or 3 Destroyers under normal Co-Op Matchmaking Rules. However, if a player waits in queue for more than 25 seconds, those restrictions can be relaxed to a max of 4 Battleships or 4 Destroyers.