LaagLanders DME - Reltive Fermentables

Can anyone take a guess? If I have a three pound bag of LaagLanders Light DME, how would that equate to a normal DME (in pounds) in terms of fermentables?

In other words, is a 3lb bag of Laaglanders equivalent to a 1.5 lb bag Muntons DME in terms of fermentables?

I'm looking for a nice session American Pale Ale and want about a 3.5 - 4.0% AVB.

Thoughts?

I had a batch that used quite a bit of Laaglander, and with an OG of 1.062, it stopped fermenting at about 1.036. It really should be used just for adding body.

On a side note, I added some Beano, and for the last four weeks, it went from 1.036 down to its current 1.018. Every day it sinks just a little bit lower (which is actually a huge pain in the ass because I want to bottle, hence the name PITA Porter).

Here's the recipe I'm leaning towards...using a lot of inventory hops and dry yeast I have.

I'm looking for a wider audience session beer so not too bitter (23IBU)...not to heavy (3.8%).

I'd love some feedback as I'm not sure if I'm going to destroy the world with my Hops schedule.

EXTRACT
Batch Size: 5.00 gal
Boil Size: 2.43 gal
Estimated OG: 1.048 SG
Estimated Color: 6.2 SRM
Estimated IBU: 22.8 IBU

Boil Time: 40Minutes (NOTE: I'm shortening my brew time and hops boil to prevent the DME from caramelizing. I want a light colored beer.)

Ingredients:
------------
1.00 lb Cara-Pils/Dextrine (2.0 SRM)
1.00 lb Caramel/Crystal Malt - 10L (20.0 SRM)
(Steeped at 158 for 1 hour)

3.00 lb Extra Light Dry Extract (3.0 SRM)
3.00 lb Extra Light Dry Extract (Laaglanders)
(DME Boiled for 40 minutes)

0.50 oz Northern Brewer Leaf [8.50%] (40 min)
1.00 oz Cascade Pellets [5.50%] (30 min)
0.50 oz Fuggles Pellets [4.50%] (10 min)
0.50 oz Hallertauer Leaf [4.00%] (10 min)

1 Pkgs SafAle American Ale (DCL Yeast #US-56)

I'd appreciate any tips or suggestions. THis batch will get kegged in my new Sanyo setup in a couple of weeks and will likely be my "show off" beer when I unveil.

Thanks