At Delta,
Aircraft.......... ECON...SL1..OT1
B-767-200.........81......54.....243
B-767-300.........94......63.....377
B-767-300ER....113.....75.....377
B-767-400ER....107.....71.....---
ECON is for minimum cost operations
SL1 is somewhere around two-thirds of the ECON for even better fuel economy when tailwinds or time-ahead-of-schedule allows
OT1 is used for headwinds or when behind schedule
MNF and MRG values are usually 0 for min fuel or max range