As long as the only cost to repair are the charges the Multi-Tool uses, the current cost is excessive. At the least it should be equal to the removal cost, otherwise you might as well remove the item and replace it.
That being said I wouldn’t be apposed having provide a resource for the multi-tool to rely on. If you make the assumption that damage = loss of mas, then it’s reasonable you have to replace that mass.
If damage = dented then I don’t think there’s any purpose in adding any additional repair costs.
In a real world condition there would be no simply picking up the block. It would take a great deal of time and energy to ‘harvest’ a solid plate of steal. Now blowing it up is another story. But you don’t harvest much if you blow it up if any at all.