Keep it clean this time. Unless the other topic was closed for other reasons (other then the fact the topic was being derailed), and mods feel the need to close this one, go right ahead.
Just posting my findings.
With all my enhancing gear (enhance @ 299 skill, no merits), i can confirm at merit #4 on phalanx2, phalanx DOES overwrite phalanx 2.
With no enhancing gear, phalanx and phalanx 2 overwrite each other.
XI Wiki

