When is it worth reconfiguring the seats for better quality ones? What size planes or routes benefit the most from this upgrade? Thanks guys
Edit- Another Q... Do Engines with the same family name but different numbers at the end count as commonality? For example the Rolls Royce Tay 620s & 650s?
Usually only when you have competition. The seats take more space than you get from higher ticket prices, so your income will most likely lower, unless the route has less demand than seats in your plane in the beginning.
you can change in such case: a plane's range is less, than actual range flown, or if route demand is less than seats offered. you can put better seats, whcih means you can put less seats into plane. anyway the excess will not be used.
as to engines commonality - as far as i see - the same engine with different numbers in the end - it is the same engine used specifically to fit that plane. i see that price for fleet/engine commonality is not increased.