Quote from Elmo
on the 23rd of April 2013:
Why do I sometimes earn fewer League Points per win when I'm close to reaching the next tier?
Since tier upgrades are permanent in the League System, you have to demonstrate you can maintain a higher level of play before the system will allow you to start a Promotion Series. In rare instances, this means that your LP earnings will be normalized until you meet this bar, so you may need to win a few more matches to trigger your Promotion Series. This is most likely to occur if you're closing in on a spot in the Challenger tier, since you have to outperform a current member of that tier to be promoted.
Quoted from Riot.
yup only applies from going up tiers not divisions. So your losing more than you gain because you have low MMR. Im guessing you have more losses than wins? to achieve low enough MMR to lose more than gain?