I think it's literally a case of it was getting done with or without the Irish government, so they took the "all members will have a minumum of at least 15%" to

I think it's literally a case of it was getting done with or without the Irish government, so they took the "all members will have a minumum of at least 15%" to "all members will have a minimum of 15%" change so they had something to present as a win and to avoid a later discussion raising the minimum further.