Rate table shipping showing $0.00 only for certain products

Question

I've added four nearly identical products to my brand new Magento 1.9 store. Each one with complete information, including weights.

Then I set up a shipping rate table, and successfully imported the CSV. I confirmed this in the "shipping_tablerate" db table using phpMyAdmin. The CSV that I'm using for debugging looks like this:

Country,Region/State,Zip/Postal Code,Weight (and above),Shipping Price
USA,*,*,0,1000

This rate is reflected correctly for one of my products when I add it to the cart and estimate shipping. However, for my remaining three products, it estimates shipping to be $0.00.

I can't figure out what is causing this odd behavior for the life of me.

65 lb product (??? $0.00 rate)

85 lb product (correct $1000.00 rate)

Any ideas? I've burnt most of the day on this problem.