Was Sakaki telling the truth when he said Zen is younger than Raj?

In volume 4 of Snow White with the Red Hair, Zen, Shirayuki, Kiki, and Mitsuhide had their ages revealed by the author, and Zen is said to be older than Raj. In a Volume 7 side story, however, Sakaki said that Zen is younger than Raj. Was this a lie to try and make Raj meet up with him, or was it other reasons?