Heal Corruption in Isengard

[Falenthal]

I was wondering, due to the interesting grey shades of Isengard and Saruman during the proposed timeline, if the undertaking Heal Corruption shouldn't have some specifics when in Isengard.
So as spending a Fellowship phase in Erebor might lead to some Shadow gain, I'd throw some ideas:

*Heal Corruption can be made with Craft or Lore tests, but not with Song.
*Being in the company and with the materials of the Wisest of the Wise, and a servant of Aulë, grants that every succesful test of Craft or Lore automatically counts as an extraordinary success. But Saruman oversees everyone in his domains, and slyly manipulates everyone to his own schemes, profiting from their works or discoveries. Therefore, 1 permanent Shadow point is gained for each succesful test done in Isengard.

-> That means that, if Isengard is a Sanctuary, and a character takes the Heal Corruption undertaking, he'll roll twice: every success grants a reduction of 6 temporary Shadow points, being thus able to reduce 12 Shadow points by simply succeeding in both tests. But every success also grants 1 permanent Shadow point.