May be the end of the "single" life, but not the end of the manga, as we still need to see the wacky things that would need to occur "WHEN" they get together.
The difference is that Tanabe's advice was after him saying he throws that shit at every girl in hope it sticks while the senpai said it in a serious way while highlighting he's concerned about both Jun and Tomo's happiness.
The different with Tanabe is Senpai was seriously love and care for Carol. He truly mean it when he said it.
While Tanabe just look unrealiable, fooling around, and so-so. He did his confession just way too light.