Need Advice for Baking Issue

So I make NY style with a 3/8 in steel near the top of my oven at 550 degrees.  When I use Charlie Anderson's white sauce (ricotta, lemon juice, heavy cream), I get a nicely browned crust including along the rim for my white slices.  However, when I use raw tomato sauce (Redpack) for a regular NY pizza, the bottom browns nicely but the rim is pale.  Why is this happening and how do I fix it ?  Thanks.