Draft of a fired heater

I’m a chemical engineer learning about fired heaters. I’m learning about draft and I picked this out of a textbook-

For example - Drafts:

• Just above the burners = $-0.3\text{in H}_2\text{O}$
• At the bridgewall = $-0.05\text{in H}_2\text{O}$
• At the breeching = $-0.6\text{in H}_2\text{O}$
• Above the stack damper = close to zero.

Why is the draft at the breeching more negative than the draft just above the burned and at the bridgewall ? Isn’t the draft when moving up the furnace be less negative ?