Seeding/sodding can be done anytime before or after using Scotts STEP 4 Fall Lawn Food Fertilizer as it does not interfere with the seed germination
Per the Scotts Step 1 Crabgrass Preventer info they recommend applying this STEP 1 in early spring which is from February to April and get a thick and vibrant lawn. If you have not used a pre emergent (weed preventer) at this point in the year, you may not see any success from this application and may need to move straight to Scotts Step 2.