[Mylon]

Is what would be nice is if upgrades, instead of currently modifying the cost of the new facility, applied a percentage of the old facility towards the new one. This way the strategy of building a 15kT minor city and upgrading to a 100kT metropolis would cost something on the order of 92.5KT (15 + (100 - 15*50%)) rather than the current system of 65kT (15 + 100*.5%).

But of course, something hardcoded and requires us to bother Aaron, not PVK.