Hmm, that might be a bit too black and white... have you thought about using km for economy tix and upgrade with coupons? It is the cheapest option.

An analysis NYC-LIM-NYC to prove the point... Remember these are red-eyes so I'll consider Business is the only good option. Remember, from June 1, 2011, you can use your upgrade coupons to apply for upgrades for tickets redeemed using LANPASS Kms. Remember odds for coupon upgrades favours Comodoro.

Economy revenue ticket is about $1k
Upgrading to Business costs 25k x 2 = 50k Lanpass km ($500 if km bought on sale).
Total: costs about $1500 and gives 12k Lanpass kms + bonus

Economy Lanpass ticket costs 48k Lanpass kms + $66 so about $500
Upgrade to Business using 4 Upgrade Coupons – free (but risky for red-eyes)
Total: about $500 and gives no Lanpass kms

Economy revenue ticket (in LE or higher) is about $1200
Use Comodoro unlimited upgrades – free (some risk)
Total: Costs $1200 and earns 12k Lanpass kms + bonus

Business Lanpass ticket costs 100k kms + $66
Total: Costs about $1k + and gives no Lanpass kms.

Business revenue ticket costs $3100
Total: Costs $3100 and earns 14k Lanpass kms + bonus

Summary (in order):

Econ T Lanpass tix plus coupon upgrade costs about $500 (earns no Lanpass kms)
Bus U Lanpass tix costs $1000+ (earns no Lanpass kms)
Econ LE+ revenue tix plus Comodoro upgrade costs about $1200 (earns 12k - 24k Lanpass kms)
Econ T revenue tix plus km upgrade costs about $1500 (earns 12k - 24k Lanpass kms)
Bus I revenue tix costs $3100 (earns 14k - 28k Lanpass kms)