If you name a TA when you book while onboard, you will get
DCL's OBC as well as the TA's OBC, which can be up to double the amount DCL offers. I use Korrine with Cruise Adventure Travel at
Korrine@cruiseadventuretravel.com. She has been great to work with, and has offered the most OBCs of anyone I've seen. We didn't know any better when we booked this on onboard, but transferred my ressie to her back in November and she gave me an additional $225 in OBC for the transfer. She said it would have been about $400 if I had named her first. Anyway, it costs us nothing to use her, and it hasn't hindered my "control" of my reservation in any way (I've still been able to contact DCL and make changes if I needed to, or I've e-mailed her and she is able to make them for me). She is a cruise expert, and used to be a Disney CM. She loves working with DCL.
Anyway, enough of my 'sales pitch' for her. I am still just so thrilled that I found her! It is well worth it to me to have more OBCs and let someone else worry about contacting DCL if anything goes wrong or needs changing.