Your phone must be on a slow provisioning list to just get MDL but not pick up MF9 yet which was released in July. Give this a try first: QbKing77 | Your Tech Simplified
, then bounce through his site for the MF9 root tutorial.
Samsung Galaxy S® 4 MJA Rooted with CF Auto-Root Tutorial
HTC EVO Design 4G™ v4.0.3 Bootloader Unlocked & Rooted with HTC SuperTool v3
If it ain't broke, use a sledge hammer.