AFM Question on the APV

I have an AFM question on the APV:

I understand we use APV only if there is a change in the Company Gearing Structure. Gearing structure = Debt + Equity.

According to IFRS 9 irredeemable debt is a type of equity.
My question is, why should we use APV if part of the gearing structure is made up of irredeemable debt when we know irredeemable debt is technically equity….. Thus in my view there is no change in the gearing because irredeemable debt=equity??

Please Assist