Unfermentable sugars (lactose) and gravity

I'm probably just confusing myself thinking about it, but does the additions of unfermentable sugars affect the 'true' gravity of the beer? My case was BierMuncher's Black Pearl Porter. I had a preboil volume of 1.060 and OG of 1.064 just before adding the yeast. The boil itself called for 1/2 pound lactose. The lactose will contribute in the gravity right?

OG was 1.064 and finished out FG 1.030. That is 4.44% Do you think it's really 4.4% or higher because the hydrometer will take into account the unfermentables?

I'd like to believe that it actually finished out at something like 1.020 and is more like 5.75%. I could be fooling myself though. Thoughts, input, etc.

Yes lactose adds directly to the OG and will carry over into the FG Lactose is something like 1.035. If you read your hydrometer correctly then yes the FG is 1.030

Bucks, all the dextrins (limit dextrins, etc) and various highly carmelized sugars left over after a mash are like lactose in this regard; unfermentable but contribute to OG and FG. You've been measuring them before, just like the lactose in this batch.

ok, so my readings are correct. 1.064 - 1.030 x 131 = 4.44% beer. I'll take that on a sweet porter. Easy enough then.