I think the Preference shares should be recorded in the Goodwill computation. Recording it in the net assets aquired account makes you apply the acquisition percentage (75%) instead of its own percentage (40%).
w.3 Goodwill P.C Equity and Preference 250,000 FV of NCI 106,000 Less: NAA (300,000) Preference (0.4×50) (20,000) Goodwill 36,000