I don't secondary anymore (I primary for 3-6 weeks, then keg). Only if I am dryhopping, adding fruit do I secondary - which I rarely do. However, with a higher gravity beer, it will need to age more (usually), you can bulk age it (secondary) or in the bottle. I've heard of people leaving beers in primary for a long time, I've gone as long as 3 moths with no ill effects.
PS: Did you do the NB Kolsch? Mine turned out great. That I did secondary and lagered for 4 weeks @ 42ºF in my root cellar.