The $25 per lot fee is a puzzler since this is not
ebay. DC can simply choose not to take a consignment that isn't worth their while. While you can negotiate the overall consignment fee don't expect it to be less than any other House. Even if you were able to get 10%, the $25 fee on a $100 lot adds 25%, 10% on a $250 lot and so on. Paying $25 for passed lots is egregious. I would never consign to them myself under these terms.
Edit to add:
DC has 45 business days after the sale to pay you. That's nine weeks.
If they break your WW collection into 50 parts and half don't sell you may end up owing them money.