Working on it..
Level 1:
Cost: $25,000,000
Output: $200,000
Iph gain: $16,667
Total iph: $16,667
Cost per this iph: $1,500
Level 2:
Cost: $41,500,000
Output: $400,000
Iph gain: $16,667
Total iph: $33,333
Cost per this iph: $2,490
Level 3:
Cost: $69,000,000
Output: $700,000
Iph gain: $25,000
Total iph: $58,333
Cost per this iph: $2,760
Level 4:
Cost: $115,000,000
Output: $1,100,000
Iph gain: $33,333
Total iph: $91,667
Cost per this iph: $3,450