Hops in my oatmeal stout

Hello all, for a Christmas gift for some of my friends, I wanted to brew an oatmeal stout. When I enter my recipe here: http://hbd.org/cgi-bin/recipator/recipator?9290819#tag I use the Tinseth method of calculating IBU. With a 2.5 gallon boil, and a 5 gallon finish, with 4 oz of 5.2% Goldings for 60 minutes, and 2 oz of 5% Fuggles at 5 minutes, it yields an IBU of 30 which is exactly around what I'm looking for. A hint of bitterness yet ultimately very smooth. Yet if I change the IBU calculation to the Rager method, I get an IBU of 62 which I believe would be way too bitter for an oatmeal stout. Anyone have thoughts on this???

I am not an expert on this but that sounds like a lot of hops.

pellets or plugs? that could be why it seems so high

For leaf hops beersmith has the IBU's @ 39.3 Tinseth
Pellet 43.6
Plug 40.1

<EDIT> I corrected the numbers for the batch size

They're whole leaf hops I got from freshops. I bought that quantity based on what I got out of the beer recipe site. This is the recipe I'm using:

9lbs dark malt extract
1.5 lbs Rolled oats (quaker quick)
1/2 lb black patent malt
1lb 70-80L Crystal Malt
1lb roasted barley
4 oz molasses

4oz goldings 60minutes
2oz fuggles 5 minutes
1 teaspoon irish moss

Is the Tinseth method the preferred? Why would the two methods yield such different numbers?

Your beer is too strong for a regular oat stout, it's more like a russian imperial stout. You will have a lot of hop bitterness and aroma/flavor if you use that many hops. You might want to cut back on DME to around 6lb DME and only 1.5-2oz bittering hops. That is, unless you want to make a rusian imperial stout.

I was using the 9lbs of Dark Malt Extract because it's liquid. I thought for liquid you needed to use more than if you use dry malt extract. What if I cut the hops back to 2oz of the Goldings and 1oz of the Fuggles, would that be better? Although, an Imperial Stout with the taste of oatmeal wouldn't be the worst thing in the world. Since I'm so new to this, I'm just not sure if it would turn out that way.

So you are using LME, I see, 9lb makes sense. If you cut the hops down like you said it would be more balanced, you could cut them even more because oat stouts are usually sweeter. One thing I would suggest, use light extract in place of dark. Two reasons; you don't really know what makes the extract dark, and you are adding a lot of color by using black malt and roast barely there is no need for dark extract.