Yes, that's something I'd like to see too... it's clear, that the reinstalling also takes time and costs something (and this could be much for e.g. the C-seats I've seen in Swiss-aircrafts, since they're really complicated things)... but... there's also others. And they don't have to be bought every time... so, maybe the price for chaning the arrangement could be... I don't know... Y 10%, bether-Y 20% of the price... C up to 40%... 50% ? ... but not 100% for every seat... and, if I'm chaning from 2F - 8C - 130Y to 8C - 135Y ... it should be clear, that the 130Y from the first configuration can be left in the plane and that only the first 3 rows have to be remodeled... at least in planes like the MD80.