Not much help but just wanted to say I feel very sorry for the OP.
Gone above and beyond here to make the install simple for Chorus and has done something that will more than likely be far better & more resilient than a 'normal' install would have been, and then gets a massive kick in the guts with the pricing.
Guess Chorus have got to make money somewhere but it's a bit of a shame they can't offer some flexibility in a situation like this.