Greater Invocation: Plundering Dispel

[Barbarian MD]

So, Devour Magic stinks as a Greater Invocation (greater dispel, but as a touch attack, and you gain temp hp), and Relentless Dispelling is so awesome as a Lesser Invocation (dispel in this round and the next), so I thought I would simply combine them, and then ask if it's balanced.

Yes, I know it's not very creative or insightful, but I think it'd be a practical change.

Devour magic stinks as a Greater Invocation. I thought I'd make something new.

Plundering Dispel
Greater, 6th

You may use the targeted version of Dispel Magic, Greater, as the spell. On a successful dispel, you may appropriate for yourself (or for any ally or allies within 30 feet) spell(s) with a total number of levels equal to 1/2 invoker level. (For example, an 18th level invoker may plunder a single 9th level spell, or a 5th and a 4th, etc.) You know how many rounds remain on all spells before you choose which one(s) to steal--the duration remains unchanged--but the spell(s) (once it becomes active on you) is treated as being at your caster level or your foe's, whichever is higher. When stealing multiple spells, these may be distributed among allies as you wish.

Make a single spellcraft check (15+highest spell level). If you fail this check, yet want to plunder spells, draw blindly from a list of spells until you wish to stop or reach the spell-level limit, whichever comes first.

In addition, if you choose, you may instead deal damage to your foe and heal yourself or allies within 30' a total of 5 HP per spell level you could have stolen. You may choose to steal a combination of spells and HP.

Finally, this invocation may be used to counterspell, as Greater Dispel. No spells are plundered when using this invocation in this manner.

Greater Relentless Dispelling
Greater; 6th

You may use targeted version of Dispel Magic, Greater, as the spell. In the round following, the target of this invocation is subjected to another targeted dispel at the start of your turn.

So my question is: is this balanced as a Greater Invocation?