I think he had a crush on Shoichi, but wants Shoichi to be happy so ships Yuuichi X Shoichi [hence telling Shoichi likes Yuuichi]. If that is true, it would be more interesting breakdown of Haruki, of him deciding between what he want and who he want to support.
Viewing post in Version 0.59 (Haruki) - Public Release comments
it would be so crazy and i really like the idea, Haruki starting to feel something for shoichi and yuuichi making him to think about if him deserves to be in a relation ship with the person who his own crush (shoichi) is in love with. It would be a different approach since in the other routes we have a shoichi being so jealous and brokenhearted so in this route we would have a triangule more complex