Maintenance Costs

So... What's up with corporation maintenance costs and their seemingly gradual increase? This affects both state and enterprise corps. New change?

Added note: It appears that the cost for maintenance units in general on KB have steadily increased as far back as I can see. Moving from 460K to 600k within one year's time. There is a huge surge in demand for the product. I see some more corps for the product are being built. Any ideas what happened?

Actually, in comparison with WG, it appears that this is a price rebound on KB...

These maintenance products are produced by corporations.
values fluctuate.