when going down in ownership but not loosing control we valued the change in nci by simply adding post aq profit to initail fv of nci and doing the caluclation.
But when goin up in ownership we calculated the chnage in nci by taking a percentage from net assets at reporting plus goodwill.
No consistency between the way this is applied in questions (or life)
My advice
Proportionate goodwill – base change in NCI on % NA Full goodwill – base change in NCI on % (NA +goodwill)
Remember that the marks now are for explanation not computation – the key point is to state that whatever adjustment is made goes to equity not P&L or OCI