787-8 and -9 very low price compared to 787-10 and A350

I know, it's complicated to calculate always at right prices because of inflation etc., but It seems these prices of these very comparable aircraft are way different, it should be fixed somehow.

Price lists for 2014 by Boeing and Airbus show that A350 is a bit more expensive, but not this much, and I suppose in 2015 there might be even less difference with € falling after ECB's QE.

I suppose maybe there should rather be inflation-adjustment to some AE standard and lowering prices for 787-10 and A350 instead of higher prices to make 787-8 and -9 more expensive? Because older models are listed in AE at much lower old prices then they're currently offered at (e.g. A320 and 738 around $50 million in AE, and IRW they cost more then 90 million in 2014)