The same thing happened to me but ive noticed that the majority of players i play with on my smurf are all under 100, where as on my main account they are usually 200-300.
I've also noticed a huge difference in matchmaking times between the two accounts. The only conclusion I've come to is that there are a lot more players in my skill level between 200-300 than sub 100.
My region has comparatively less players, so it wasn't the case at all. This image is more or less representative for my smurf account.