Dry hopping with top cropping yeast?

I fermented a beer using Wyeast 1318 London Ale III.  When it came time to dry hop there was still a nice layer of yeast on top of the beer.
  I racked from the Better Bottle to 5 gallon carboy, and added the hop pellets. I kept the carboy at room temp. around 67°f. By the next day there was a new layer of yeast on top of the beer. I let it sit for a week cold crashed it with gelatin for a few days and then kegged it up. The beer is good but I did’nt get a lot of the dry hop aroma I was expecting. I think maybe the hop pellets mixing with the yeast might have something to do with this.
  I have another beer ready to dry hop using the same yeast.
  Should I transfer it, cold crash and keep it cold while the dry hops are in there? I have read that that dry hopping at colder temps. isn’t the best way? Or maybe dry hop in the keg?

Dan

I prefer to dry hop at warmer (68F) temps, but there is definitely no consensus on this. I have dry-hopped on top of krausen before with no issues (but it was a pretty heavy dry hop amount). My recommendation is just to wait until the krausen has fallen back into the beer before you dry hop if this is a concern.