A production system and a frac sleeve assembly of a frac assembly of the production system. The frac sleeve assembly includes a funnel section that reduces in diameter in a direction of an outlet of the frac assembly, a throat section having a selected diameter, and a ball seat at an intersection of the funnel section and the throat section for receiving a ball. When seated in the ball seat, an entire portion of a ball extending into the funnel section is exposed to disintegrating fluid in the funnel section.