As I have long said, I did not expect a cost sharing deal to get done before the April 15th Korean parliamentary elections and it appears that will be the case:
U.S. President Donald Trump has rejected South Korea’s offer to raise its contribution to shared defense costs by at least 13 percent, a news report said Friday.
Trump made the decision last week after consultations with Secretary of State Mike Pompeo and Secretary of Defense Mark Esper, Reuters said, quoting unidentified current and former U.S. officials.
Esper made a phone call to South Korean Defense Minister Jeong Kyeong-doo earlier this week to press Seoul to quickly agree to much higher contributions, it said.
Yonhap
You can read more at the link, but politically there was no way the ruling party would agree to a major increase in defense spending. By the Trump administration turning down the modest increase, the Moon administration can go into the election saying they tried, but the Trump administration is too greedy and that is why all you Korean employees that work on U.S. bases are laid off.
The next decision by the Moon administration will be if they want to wait until after the U.S. Presidential election to make a deal.