youre reading too much into this. this QFR is one of those explicit clarifications of something that already existed. specifically the change in terminology was adopted some years ago. id have to look it up but i would estimate on the order of 5 years ago. i specifically recall a WT study on the subject.
the change is mostly semantical. it has about as much significance as the change from 'vindication' to 'sanctification' of gods name. however, it is a very interesting example of a progression in perfection attributed to sacred personages, taken to ridiculous extremes. the main idea is that we would not want to attribute any negative wording to any aspect of jehovah, in fact, anything less than absolute perfection. and the word 'temper,' implying an inner conflict is enough to qualify. other famous examples are the doctrines of perpetual virginity and immaculate conception. the catholic church couldnt have mary simply be holy enough to bear the christ solely by holy spirit. she herself progressed to being free from sin and sex altogether.
the way jesus is treated in the progression of early christian thought is similar. in chronological order: in pauls letters, jesus is holy from resurrection. in mark, jesus is holy after baptism, in matthew/luke, holy from birth and finally in john, many years later, holy from the very 'beginning' of creation. in post-apostolic tradition of course, he then became equal to god in every way.
the WT follows this pattern often, the doctrine of selective foreknowledge is the best example i can think of. its a ridiculously awkward doctrine borne from the unwillingness to ascribe to jehovah the slightest bit of ignorance of anything at all.
mox