This may also be endemic to WaW, note, but putting it here because I noticed it in WiE...
Trying to repair the Regia Marina after winning the Battle of the Med (3 enemy CV's BB's lost each, several cruisers too, have all of my battlewagons & a couple of CA's), kept thinking, "Damn this is expensive as Hades..." It was typically costing me 193 MPPs to repair half a BB (5 points), which at this stage of the war represented almost all of Italy's income. [tech wise they had +1 Naval & +1 AA]
Went in to the build menu--and quickly noticed that that represents HALF of the cost of a brand new BB!  For all of the iterations of this game I would have sworn that all units cost less per point to repair than to build. For ex. 10 points of a repaired medium bomber would cost me 160 MPPs, while a brand new one would cost 345, incl. upgrades. For a tank corps it's 140/288, so apparently the repair cost would be a bit less than half the purchase cost. Subs 110 vs. 230.
So why the extra costs for surface ships?