Weapon Exp. Question

[Yip9]

...because i want to get Lara to Level A in swords:

Does a character gain weapon experience when the character hits an enemy unit and does zero damage?

As always, i am grateful for the help of you FESSers.

[Neofox]

As with the FEs to follow, FE5 grants you weapon experience whenever you use a weapon, even if it misses or does no damage.

It's for this reason that some people abuse broken weapons, I believe... Odds are you won't hit with them, and if you do it won't do much, so it helps get the weapon level up (which is nice since they grow fairly slowly in this game).

[Sakura]

I also have a question on weapon levels...

I made Nanna use a warp staff on the first turn on chapter 18, and she raised her staff weapon level by one.  After a few turns, Leaf died so I had to restart the chapter.  I made Nanna use the Warp staff again... but this time she didn't raise her staff level.  I made her use a Heal staff after, and she still didn't raise it...  o_o  Why does this happen?