Fix Costs for Better AI

Skewed unit cost relative to combat value can cause an AI that considers cost to perform poorly when attacking or buying so use costs that reflect combat value.

Compare AGW estimates against PG unit costs:

AGW...PG
42.........96.....Polish cavalry
99.........72.....Polish (AF) 75mm artillery
78.........24.....Polish TK3 tank
45.........24.....Polish (AF) 37mm ATG
30.........24.....Polish infantry
39.........24.....Partisan
63.........12.....PzIA tank

Note:

• Polish cavalry is worth half a 75mm but costs a third more
• Polish cavalry is worth about the same as partisans but costs 4x more (Polish cavalry Ground Defense (GD) of 2 is weaker than partisans, as weak as artillery, and as weak as 1939 Polish infantry while mounted in trucks)
  
• Some units cost double what they should (Polish cavalry)
  
• Other units cost only 1/3 or 1/5 what they should (TK3, PzIA)
  
• AT units need to be discounted (discount included in $45 price) because, unlike other units, they have class penalties (AT penalty) with no offsetting class advantage but the PG 37mm $24 stills seems underpriced
  
• AT and AD costs are grossly inconsistent within their respective classes
• Efiles that raise cost for rairity or to discourage purchases will fool an AI that considers cost into making bad decisions
• An AI that generates its own estimate of combat value instead of using efile cost will avoid being fooled by efile costs that do not reflect game/combat value
  

A test of AI purchases in the PG Poland scenario suggests that the PG AI might buy underpriced units.