The China-South Korea summit lasted 97 minutes... Why was it 10 minutes longer than the US summit?

The summit meeting between President Lee Jae-myung and Chinese President Xi Jinping lasted 1 hour and 37 minutes, which was longer than the meeting between President Lee Jae-myung and US President Donald Trump (on the 29th of this month).
It was revealed that the talks were about 10 minutes longer than the previous one (1 hour and 27 minutes). While various interpretations have been exchanged regarding this, some political figures have cited the "failure of the US-North Korea summit." President Donald Trump
One of the main points of interest was a surprise meeting with North Korean leader Kim Jong-un, but it was analyzed that this did not take place.
It is speculated that there was nothing more to say since the talks were essentially concluded. Meanwhile, substantive dialogue between China and South Korea was held with President Xi Jinping, and the meeting lasted nearly 100 minutes.
It is believed that the meeting included discussions on peace in Northeast Asia, centered on the denuclearization of the DPRK, as well as issues concerning civilian life. In particular, President Lee Jae-myung requested China to take measures and cooperate in preventing North Korean nuclear proliferation.
Furthermore, issues related to the livelihood of the people were also discussed. As if reflecting this, after the meeting with President Xi Jinping, there was talk of a mutually beneficial business cooperation between China and South Korea, such as a won-former Chinese currency swap.
The two countries also signed an MOU on cooperation against international crimes, such as voice phishing and fraud, which have recently become hot topics in Korea, and the MOU has been praised as being "useful for the public's lives."
Meanwhile, the meeting between Prime Minister Sanae Takaichi and President Lee Jae Myung lasted about 45 minutes. Unlike the leaders of the United States and China, there was no dinner between Japan and South Korea.
However, with Japan and South Korea promising to resume shuttle diplomacy, it is expected that there will be substantial exchanges between Prime Minister Sanae Takaichi and President Lee Jae-myung during his next visit to Japan.
President Lee Jae-myung also promised another opportunity to meet again at a press conference after the APEC summit on the same day (1st), saying, "Let's meet in Nara Prefecture, not Tokyo."
Meanwhile, President Donald Trump and President Xi Jinping visited South Korea as state guests.
We prepared to treat him as a guest.