I just bought the game on Xbox and grinded up to lvl 25 and played my dps placements went 4 to 1 and the game after my placements i lost 100 sr in a lost game is this supposed to happen I watch other Overwatch streams and they never lose this much sr from one match.
They’ve explained this in the Role queue update post:
Why did I complete placements and receive an SR that was too high/low?
If you’re a new player, placements are straight forward. You start at a “new player baseline” SR and when you win games your SR goes up, and losing games lowers your SR. New players are also set at a higher variance level, so the amount of SR you gain and lose is multiplied higher. The matchmaker does this because as a new player it knows very little about your skill and wants to determine it as fast as possible. The increased variance slowly decreases as you play more and more games, and the matchmaker is more confident in identifying your skill.
If you’re a returning player, placements are still simple. Instead of starting you out as a “new player”, we start you out at your “historic baseline” SR that covers more time than just the previous season. Your SR then changes as you play your placements, but since you’re not a new player we use the base variance level. This means that you’re unlikely to see radical change in SR from one season to the next, but that reflects the fact that your actual skill at playing Overwatch doesn’t radically change either.