I shot a few rolls of Delta 3200 over Christmas and i think i agree about developing it for 1 stop above what you shot it at. I shot all my rolls at 3200 and developed it at 3200 in HC-110 (B) and the negatives are not dense enough for what i think they should be. All rolls were shot in my F80 which has a pretty good meter yet most shots on the negative look way underexposed. I will definitely develop for the 6400 times next time i use it. I used Kodak's agitation recommendations for one roll (5 seconds every 30 seconds) and Ilford's D3200 agitation recommendations for another (10 seconds every minute), both for the same overall time.
Only other thing i'm trying to experiment with is controlling the grain. I accept it's a grainy film which is fine, but when i look at the negatives on the enlarger the grain looks like non uniform clumps of mud or popcorn, just doesn't look right..Not sure what's going wrong...I think i might try using DD-X to develop it in next.