Ranked Lp Query

So, I'm new to the whole ranked thing, I'm on gold 5 promos, so I have to win 3/5 games right? Well, I'm wondering why my Lp has gone down after losing the first match of the promos (shows 85, not 100). I didn't think you would go down LP until you lost the promo stage completely? Or is this normal? Thanks
Report as:
Offensive Spam Harassment Incorrect Board