The posts above are right on the money. For whatever reason, PSE prints a 6 grains per pound of peak draw weight minimum arrow weight on all their bows. Since you have a 60 lb peak draw weight model bow then their suggested minimum arrow weight when the bow is set at 60 lbs would be 360 grains.

This is somewhat misleading though for several reasons. One, if you are shooting less than the peak weight of your bow then, going by their reasoning, you should be able to shoot less than the minimum arrow weight listed on the limb. Two, it fails to take into account the fact that 6 grains per pound of draw weight is a specific ATA recommendation for those shooting at a 60 lb draw weight and a 30 inch draw length. Shooting a heavier draw weight or a longer draw length, technically, requires a heavier grains per pound of draw weight ratio from the ATA. Lastly, though they suggest shooting no lighter than 6 grains per pound of peak weight PSE regularly shoots their bows below that listing otherwise they could not advertise an IBO speed rating as that is at a 70 lb draw weight, 30 inch draw length while shooting at 5 grains per pound of draw weight.

Hope this helps.