Tip break in
This is how I do it.
Break every rack you play with it for about a week straight. (assuming you play about 2-3 hours a day) but do not shape it. Also dont hold back on your breaks, hit them as hard as you can without misscueing.
By the time you are done with that it should be mushroomed out pretty good and kinda flat on top.
Then shave it back down flush with the shaft and burnish, I use a porpers grazer and burnisher for this. Re-shape to your desired radius and that should hold for you. I use a pick from time to time just to help with chalk retention.
If you are still having problems try cutting off a layer or two and see if that works. Hope this helps