Treatment of Inter-company Loans in Income Statement

After watching your lecture regarding the DEC 2009 Q.1 Pandar I realised that the interest on an intra-group loan should be charged only to the POST-ACQ period, thus having a knock-on effect on the calculation of subsidiary net assets, and the NCI share of the adjusted subsidiary profits after tax. However, after studying a similar question in BPP’s textbook (Q.12 Panther Group, p.385) I was again confused since in BPP’s recommended answer (p.415 of the same textbook) the above principle is not taken into account i.e. NCI is calculated on a simple time-apportionment of P.A.T. thus assuming that the intra-group loan interest accrued evenly throughout the year. I believe this treatment to be contrary even to the ACCA suggested methodology but it is very confusing. Could you please shed some light?

THANKS A LOT