Thanks Chemando for all the good info.
I just spoke with the gentleman who runs this company, and had a nice chat
I learned that:
the puck locks are flat key, but 6 pin, and a higher pin tension, so harder to pick than a lesser lock.
these locks do not go on sale... only when a new model is first introduced, for a short period of time.
shipping to Los Angeles would be $15
the 2516-A is $225 USD plus shipping. (same as what their website says)
They generally have them in stock - especially this 2516-A
They are made in the USA.
Due to more clearance needed for the hitch, on the 2516-A.... the internal lower part of the 2516-A had to be lowered, so there isn't room for the chains to be secured inside the lock.... however this model has a way to secure the chains to the 2516-A with a padlock. (the user supplies the padlock)
He said some people use the chains to secure a bike or extra propane tank or whatever, then lock the chains to the 2516-A with a padlock.