Why is Metal Mine Net Revenue so high?

I just got back to the game after about a year break.  Love it.  I've always had the OPTIONS -->GAMEPLAY-->SHOW BUILDING NET REVENUE on, so you can directionally see which buildings are profitable. 

I noticed the net revenue for metal mines (and sometimes quarries) are way too high.  For instance, just started a map and aluminum is at $20.  A high resourced aluminum tile will produce 2.0.  So, I would expect the net revenue for aluminum to be $40.  Instead the aluminum icon has $116.  If I hover my mouse over the aluminum icon, I see HIGH ALUMINUM is $40 and ENERGY/POWER is -$4, which is correct, so again, I'd expect to see $40.  So, why does the aluminum icon show $116?  

During gameplay, I noticed this same issue with quarries sometimes, but never with other buildings..