Ok, guys, how do you know if a bow is tilled for 3 under?

If I set my nock point 1/2" over center and start to pull the bow back, the bottom limb flips out first. If I set the nock point almost 1/8" over center (basically bottom of nock point is dead center to rest), then when I start to draw, the bow limbs stay pretty even but I definatly get a high flip from my arrow. I set the nock point again to 1/2" over center and it goes away.