Welcome to JOF
Towing your TV/TT combination from the dealer's lot won't give you an accurate towing experience because your in an "unloaded" condition.
Also, there is no way for the dealer tech to pre-adjust your Anderson WDH in anticipation of your TV/TT loaded weights, we all have different loading habits. Hopefully the dealer gave you the installation/adjustment instructions for your WDH.
The only accurate way to confirm that your Anderson WDH is adjusted correctly is a trip to a CAT scale under "loaded" conditions (ready to camp), the CAT scale will also confirm your critical weights.
CAT Scale TV/TT '"how to": http://www.jaycoowners.com/forums/f37/how-to-weigh-your-tv-tt-3871.html
Feel free to post your CAT scale results and JOF members will help you interpret them if you like.
There is a way to adjust a WDH that will get you in the ball-park, but you will need the WDH documentation, and also consult your TV owners manual for front suspension requirements when using a WDH.
If you run a search on the "Anderson" there are a couple threads here at JOF.