Because the clauses are badly drafted and open to interpretation, Aperture have chosen the method in their best interests, rather than the intended method that most use.
The trigger clause --- i.e --- is there enough equity to trigger equity release ... more than £5k .... is often referred to by example or reference to annex 6 or 7:
House market value x 85% less secured lending = available equity
Most IP's have used the same figure for equity release. But, to be honest, it has always been academic, as a remortgage has been impossible and the 12 month extension has always applied. Aperture now apply their own methodology to the amount to be released, which could be construed to be correct. albeit not what was probably intended. in post 2014 IVA's there is now the option of secured lending which makes the extension less likely to be the most applied solution.
Also -- on the £5k de minimis with interlocking IVA's. The generally accepted view is that, as the equity clause is worded to reflect the share of the debtors interest in the property, each of you should have the trigger amount applied to your share and so, effectively, you should have the £10k de minimis between you. However, again Aperture take a different view (and they are not completely alone) that only £5k applies for the two of you.
Posters have challenged the trigger calculation and, if the example is embedded in their proposal, Aperture have backed down in the past. As mentioned above, the actual amount to be released isn't usually a problem as the extension has, historically, applied ... but things are changing.
Posters have also asked here re the de minimis and have been told that the £10k should apply, as considered here as well as other debt forums. But none have come back with the outcome, but I suspect Aperture haven't capitulated.
Not a very helpful reply, I am afraid. Sorry.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014