i think it's also because his character is more fleshed out than the first one. here, we are given an equal amount of "getting to know" about what Kunihiko is thinking. Meanwhile, Yuu is more spontaneous and almost "what the heck is he thinking...is he even thinking?"
Its soooo rare to find couples this mature, realistic, with good communication, development and drama like these two... Asahi & Masato should be an example for others authors really
Thank you for given us such adorable and refreshing stories !! ヾ(❀╹◡╹)ノ~