Finished with attacking - that's asking too much (12)

I believe the answer is:

overcharging

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'asking too much' is the definition.
Although both the answer and definition are present participle verbs, I don't see how one could define the other.

'finished with attacking' is the wordplay.
'finished' becomes 'over' (over can mean finished or ended).
'with' is a charade indicator (letters next to each other).
'attacking' becomes 'charging' (charging is a kind of attacking).
'over'+'charging'='OVERCHARGING'

'that's' acts as a link.

Can you help me to learn more?

(Another definition for overcharging that I've seen is " Ripping off".)

I've seen this clue in The Irish Independent.

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