The U.S. is Korea's third-largest supplier of importing goods, behind China and Japan, and they face discriminatory barriers similar to ours. The most-favoured-nation tariffs are three to four times what the U.S. tariff of about 2.2% is, so Canada and the U.S. are very similar on their tariffs, and Korea is of course much higher.
So the U.S. is in favour of this agreement for the access that it will give them to the third-largest economy in Asia and for the benefits they see. They want to maintain their position as the importer of choice from North America.
I believe their rationale for wanting an agreement is similar to ours, but they are also pursuing opportunities to invest within Korea. You may know that Bell invested in Korea many years ago and exited with over a billion dollars in profit after two years, so clearly foreign direct investments into Korea can be profitable for Canadian companies as well.
As to modelling, no, we have not done that.