I was gonna cry out that this sounds preposterous, for I always thought that a wizard should "understand" (=be able to cast) the spells he copies... but it seems you guys are right.
Moreover:
RC p160
ADDING SPELLS TO A SPELLBOOK
Spellcasters who use spellbooks can add new spells to their spellbooks through several methods.
Gained Spells
Spellcasters who use spellbooks perform spell research between adventures. Each time such a caster attains a new level in the appropriate arcane spellcasting class, that spell- caster gains spells to add to the spellbook according to the class’s description and any restrictions from specialization. Spells so gained must be of spell levels the caster can cast. Spells gained in this way don’t have the time and money costs for spell’s copied or researched (see Writing a New Spell into a Spellbook and Researched Spells).
Copied Spells
Spellcasters who use spellbooks can add a spell to their book whenever they find one on a scroll or in another caster’s spellbook. The spell to be copied must be on the copier’s class spell list. No matter what the spell’s source, it must first be deciphered. Next, the decipherer must spend a day studying the spell. At the end of the day, if the decipherer can learn the spell, he makes a Spellcraft check (DC 15 + spell’s level). If the check succeeds, the spellcaster understands the spell and can copy it into a spellbook (see Writing a New Spell into a Spellbook). The process leaves a spellbook unharmed, but a spell successfully copied from a scroll disappears from that scroll.
If the check fails, the spellcaster can’t understand or copy the spell. After such a failure, the decipherer can’t learn or copy that spell again until he gains another rank in Spellcraft. A spell that was being copied from a scroll doesn’t vanish from the scroll in this case.
In most cases, wizards charge a fee for the privilege of copying spells from their spellbooks. This fee is usually equal to the spell’s level × 50 gp.
...so by raw its 100% ok.
personally... I am not sure i'd allow it though...
somehow it doesn't make cense.