Slit seeding is more. To clarify what I said up top, I was in a hurry, oops. Aeration and seeding without renovation to hardpan clay is a waste of resources, time and customer money. In most cases the grass will not do well during the heat. HOWEVER, if you have this yard year after year and compost it every season after aeration and seeding you will see greatly improved turf each year.
Everyday you wake up you have been given 24 hours. What you do with those hours determines how rich you will become. The rich work the hours you don't see.
Great Book: "Think and Grow Rich"