Match making works differently in the solo and group queues. The only way you could see an example like you describe is in the group queue.
-----
Group queue matchmaking.
- every group size has a maximum tonnage (I have no idea what the number are at the moment but you can look it up).
- as the group size increases the total tonnage allowed decreases.
- it is up to the players in each group to choose mechs that they want to play and maximize their tonnage/effectiveness
- group queue matchmaking does NOT have weight class matchmaking at all anymore.
- a 6 man group is welcome to take 6 lights ... but they may be matched against 3 2-man groups with 6 assaults.
- group PSR is the AVERAGE of all players in each group. A group with a tier 1 and a tier 5 is totally fine since the matchmaker does not constrain who you play and group with ... the PSR used for that group is the average.
Group matchmaking takes the group longest in the queue and tries to form a match with other groups of similar size that have similar average PSR. It does not consider tonnage or mechs in any of the groups since that selection was up to the players subject to maximum group tonnage constraints. If there aren't similarly sized groups, the matchmaker just fits groups of different sizes together with roughly equal PSR. It is still possible to get a 12 man against 6 2-man groups ... but this could give a match with 12 medium mechs vs 12 assaults depending on what each group selected.
----
Solo queue matchmaking is completely different.
The player longest in the queue becomes the seed. The PSR value for this player becomes the base PSR for the match.
- the matchmaker then aims to form a match with a 3/3/3/3 weight class distribution. If there is a significant wait time for some queues then it will activate a release valve changing the weight class distribution for some matches to reduce the longer queues. For example, if there are more heavies in the queue and fewer lights, it will throw in some 2/3/4/3 matches to deplete the heavy queue. During events this can get as extreme as 6 in one weight class. HOWEVER, opposing teams should ALWAYS have the SAME weight class distribution in the solo queue. so a 2/3/4/3 team will face another 2/3/4/3 team.
- However, the matchmaker IGNORES actual tonnage ... it only considers weight class ... so a Commando is the same as an Arctic Cheetah and a Victor is the same as a Kodiak for matchmaking.
- now ... after getting the seed PSR ... the matchmaker fills out both sides with as small a spread in PSR as possible while matching the weight classes on the two teams. If the match isn't completed after 1 minute the PSR range allowed increases ... it does this again after 2 minutes. There is a maximum PSR span from the initial seed allowed.
------------
So the match described by the OP is certainly possible in group queue but should never happen in the solo queue.
If you want references ... the best thread is:
http://mwomercs.com/...courtesy-phone/
Some of the information is dated and refers mostly to the Elo based matchmaker (which as far as we know is the same except for the substitution of PSR for Elo). For group queue matchmaker references you would need to dig through patch notes or townhalls with Russ.
Edited by Mawai, 08 September 2016 - 07:55 AM.