Hop quant. for 2 brewpots full boil

[kabbo]

I am soon moving to all-grain but can't afford a propane burner and ss mega pot so I will be boiling with two 5gal canning pots. I do 6 gal batches so I plan to collect 8 gallons of wort (4gal by pot) that will boil down to 3 gals each. I understand that the concentration remains the same, since 3gals of 1.050 wort added to another 3gals of 1.050 wort will simply give 6gals of 1.050.

My question is about the hops. Do I have to split the quantity in half for each pot ?? I know the utilisation is a matter of AAU and gravity (and some other factors) so the IBU in each pot will be half of the predicted IBU for the 6 gal batch.

Do IBUs add up ?? Ex: 3 gals of 20IBU + 3 gals of 20IBU = 6 gals of 40IBU ???

I read in John Palmer's How to brew :

[Senbei]

I know the utilisation is a matter of AAU and gravity (and some other factors) so the IBU in each pot will be half of the predicted IBU for the 6 gal batch.

The IBU in each pot will be the same as the predicted one, you're splitting your hops in two halves and splitting the water in two halves, the ratio remains the same.
You'll be mixing two pots with 40 IBU each, you'll get a big pot with 40 IBU.