Originally Posted by dryboroughbrewing
You're measuring specific gravity when you use a hydrometer not just sugar content, so when you add dense materials to your recipe the gravity will go up. That being said to figure out your gravity, I'd probably figure out the sugar and carbs in PB2 and add that to the value your malt extract gives you.
dense soluable material, things that sink or float shouldn't effect your gravity. But Dryboroughbrewing is right, getting the carbs/sugars per serving of the Cocoa and PB and normalize to the amount added and then to the dme should give you the sugar content for ABV purposes.
For instance, the DME has about 45 points per pound gallon - in your case 540 points/5 gallons would be an OG of 108.
So now you'd look at the PB and find it has 5gr sugar per 1 oz serving for about 165gr for what you have. Convert that to points (about 15ppg) and add that to your numbers above (either 540+15 or 108+3) - Note I'm making up the 5gr/1oz serving check labels.
The rest of your gravity is a combination of dense protien, and poorly mixed wort from the top off.