How do I go about setting up different shipping costs for different items?

The store sells large pieces of furniture. Some examples would be:

Chest - Shipping $145.00

Seat/Bench - Shipping $110.00

And so on.

I set up the shipping module for "Per Unit", turned off the other options, and set the weight to the shipping price but the price at checkout shows as $39.50 or a max of $50.00.

I am stumped.

Thanks, Mike