beersmith issues

So up until now, i have been using palmer's book and a calculator along with an ibu calculator for my droid for my calculations. I downloaded the trial version of beersmith and plugged a recipe with way different ibu's. Example of my saison: 3# pils lme (36pts per lb) 1# sugar (40pts) 1# pils dme (40pts) in a 3 gal boil. This gives a bg of 1.062. Using saaz (4% aa) at 60, 10 & 5 min then 3# more of lme at knockout. According to phone calculator, total ibu's were roughly 35 but using beersmith, i got 18. So are these calculators way off, or was it my math and why?

if you can give more of your recipe, that would help. like how many gallons (i would assume 5g), how much hops at those times ( 1 oz at each addition? )

Sorry. Hard to do by phone when swmbo has the computer horded. It was a 5 gal recipe, 3 gal boil and 1oz hop additions at 60,10,5 min. Simple ibu calc gave 35 ibu's (23,8,4.5 for additions) but beersmith gave 18 eventhough sg was same as my math using palmers values. So with same gravitiesand aau's, not sure why so far off? Probably something simple..

Pellet hops.

Beersmith is probably taking into account that you are not getting full utilization out of your hops since you are boiling in 3 gal instead of 6+ (for a 5 gal batch).

But half the malt is added at knockout. At a boil of 1.062 utilization should be constant through both programs. I checked the post boil box for half the extract on beersmith but still shows a discrepancy of 17 ibu's

Is you phone using the same formula as Beersmith, with the three different possibilities you might want to check that out. Tinseth, Rager, and Garetz.

Also I believe the default setting for beersmith is 100% utilization.