Ask an Aran thread.

no, it's not like that at all.

You get Double in first job, and triple in second. Now, you see how there's a double swing in 2nd job too, but it's hidden?

The level of 3rd job's Double Swing is going to be the same level as first job's. If you max it in first job, it will be maxed in 2nd, 3rd, and 4th. If you only put it at level 15, then it'll be level 15 in 2nd, 3rd, and 4th. Those new skills replace the older one when you promote. What this really equates to is a pretty huge damage boost right after taking your advancement test. As soon as you become a 3rd job Aran, your old Triple Swing will be replaced by the new one, and the damage % will raise from 250% to 350%. You can easily tell this because the animation will change. It's especially obvious in 4th job because the animation is so radically different.

No, Isaac, you would be wrong here. With the skill data ALONE, FullSwing is maxed at 20, but Overswing is maxed at 30. If what you said was true, Over Swing would be maxed at 20.

It should show Full swing (or over swing) in the skill book, and adds to the two hidden skills, FullDouble and FullTriple (with the over swing counterpart).

Edit: Also, OverSwing has Mastery books.