Logical Tiers (LT) >= Physical Tiers (PT)

For N Nodes in each Tier Operations Complexity Index (OCI) is calculated as
OCI = (LT-PT+1)*(N^(PT-1))

For N=4; LT=PT
3 Tier = 16, 4 Tier = 64, and 5 Tier = 256

For N=4, LT-PT=1
3 Tier = 8, 4 Tier = 32, and 5 Tier = 128