That is incorrect. You are another in a line of people who has a view which they have read in the literature before and has not actually read the correspondence.
See Post #256.
The plan was to get to the roads leading south from Iuka and in conjunction with Ord's forces strike the Army of the West, crushing in their left and depriving them of the ability to pull back either to the south, via the Jacinto or Fulton roads, via Bear Creek to the east, which was heavily emphasized as a grave threat, or due north towards the Tennessee river.
The way I see it, the operation failed due to the inability to accomplish these joint objectives, in which the Army of the Mississippi would have had to have reached the connecting road for cross support purposes on the Jacinto and Fulton roads and launched the attack in conjunction with (or rapidly following) Ord's attacks, crossing in the Confederate left and hence depriving them of the ability to cross Bear Creek via its defiles that night.