You misunderstood the article. He said 収録曲は70!じゃない!! not because there was 69 songs in regular play, but 71. He unlocked both songs in regular playcrystalsuicune wrote:
http://blog.wazap.com/111702/archives/51506411.html#comments
Never mind,the last hidden song was a lie.It never existed.
There's a total of 71 songs,including the two that appear only in Taiko dreamland.
Which means there's only 69 songs in main gameplay.
And I thought there'll be a final boss...

The first sentence says it clearly
隠し曲が一気に2つ見つかりました。(Found 2 secret songs in one go)
それは奇しくも、たいこランドで何度も演奏した (Strangely enough, they were the songs you could play in Taiko Land too)
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ゲーム雑誌にあった「収録曲70以上」は、そう言うことだったんですね…。 (So that's what the game magazines meant when they said 'MORE than 70 songs'...)
@arken: Help me re-upload My Soul, Your Beats please :3