Regarding the Battle of Iuka.
Total Union casualty estimates viewed are fairly consistent at between 782 and 790, with the official consensus estimate being 790. (See '
OR': Vol. XVII, Part 1, at page 78, and the NPS link at
https://www.nps.gov/civilwar/search-battles-detail.htm?battleCode=ms001 ).
In contrast, total Confederate casualty estimates seem to vary widely between 594 and 1,516. Am inclined to accept, with reasonable confidence, the official Confederate casualty returns for the division, comprising 1st brigade (Gates), 2nd brigade (Hebert), 3rd brigade (Green) and the 4th brigade (Martin). Division casualties returned by Hebert (who replaced the fallen Little) totaled 493, excluding any missing/captured. (see '
OR': Vol. XVII, Part I, at page 126).
In relation to brigade casualty returns showing additional counts of any missing/captured.
The 1st. brigade (Gates) did not participate in the battle and had no casualties. (see '
OR': Vol. XVII, Part 1, at page 127).
The 2nd. Brigade (Hebert) casualties return showed the additional count of 40 missing (see '
OR': Vol. XVII, Part 1, at page 127).
The 3rd brigade (Green) did not appear to submit a return showing any missing/captured.
The 4th. Brigade (Martin) showed no missing/captured in its casualties return. (see '
OR': Vol. XVII, Part I, at page 133).
The aggregate of these reported Confederate casualties is therefore, 533 (i.e. 493 + 40). This accords approximately with the current NPS estimate of 594 (refer to NPS link above). Both these estimates are substantially below some of the secondary sources seen quoting estimates of total Confederate losses in the battle.