Advanced turrets require 50 Bochilium and 0 Coalmin
High-tech turrets require 0 Bochilium and 100 Coalmin.

Is this correct?

Having built a spreadsheet that works out materials and commodities required for structures this doesn't fit the pattern I have found on all other structures.

I'm guessing it should be either 50 (Adv)/100 (HT) Bochilium or 50 (Adv)/100 (HT) Coalmin.