Mission Enhancer Package (M.E.P) allows you to enhance an existing mission giving you the hability to request support assets in a inmersive way during the mission.
You can request SEAD missions, Buddy lase, Recon target area, etc easily through the F10 radio menu.
This way you can face the mission in other way as was planned.
i.e you may do a TARCAP for a requested Ground Attack package instead of raiding the target by yourself
Or maybe a SA-15 is giving you problems? request a SEAD package to wipe them out!
Or maybe you are building a mission. Include the MEP and do not waste time planning the support packages. Leave the player to request them when and where he wants to!