Imperial Nut Brown - Add LME late?

Hi All, I'm brewing Brewer's Best Imperial Nut Brown this weekend and when I bought the kit the guy at my local store advised to add the powdered malt in the beginning of the boil and the LME with 15 minutes left, as opposed to adding at the same time as the powder. I can't remember why this was. Does this approach make sense to you guys? I think he was basically saying that there's no point in adding the LME at the beginning of the boil. Let me know your thoughts.

Well if this were a light colored beer, I'd say he was thinking of carmelization and mallard reactions darkening the beer.

He is right from the POV that you don't have to put all the malt into an extract boil at the start, but can reserve some for the end - reduces sugar concentration should reduce potential scorching/carmelization.

I'm not sure it matters DME/LME going in late, which ever you want really. I know I get more boil action when my DME goes in. (more foaming). You need some malt in the boil for hop bitterness extraction. But not all of it.

The reason someone would suggest doing a late addition is because bittering hops will work better if the wort is at a lower gravity, and has less malt extract in it. This can actually make a pretty huge difference in some cases. I use the brewersfriend .com calculator and you can put recipes in there with "late addition" and you can see that sometimes the IBUs will increase by a significant amount. Whenever I'm brewing an IPA, I make sure to do late additions for the simple fact that I can get more IBUs with less hops so I basically save some money.

As ACbrewer said, another reason to do a late addition is for if you're only doing a partial boil (boiling 3 gallons and topping it off to 5 gallons in the fermentor), boiling a concentrated mix of extract can darken your beer. Best case scenario is to do a full boil, but not all of us want to do that so you can just add the malt extract late so as not to darken or carmelize the extract too much.

Some people may say not to do late additions depending on what extract you're using. Something about a "hot break" and whether the extract was boiled enough by the manufacturer.

Thanks guys. Appreciate the input.