LP gains/losses drastically changed in one division

Hey guys I'm a little confused atm. I recently moved up from plat 2 to plat 1.

This is the what's bothering me; When I was in plat 2 i was getting 20-23lp's worth for a win and losing ~17 lp for a loss, which is alright.

But suddenly in plat 1, my gains changed to 16 for a win and 16 for a loss, then after a few games of this it has become 14+ and 14-.

Can someone explain why my lp has gone so wierd? I have a pretty good winrate, so I'm unsure of why my gains would've plummeted so.

Thanks