From 2LT WJ Haynie's record, we have:

On May 12 1862 it was the 1st Rgt Ga Partisan Rangers.
In May 1863, 16th Battalion Ga Partisan Rangers, then
in Sept 1864, 16th Rgt Ga Cav.

This last was almost 5 months after the official date - May 2, 1864 = renaming it the 13th Rgt Ga Cav.

After his capture that Sept, on the Federal documents Haynie was still using 16th Rgt, not 13th.

If it turns out to be correct that some companies were on detached service, they may not have even known about the redesignation from 16th to 13th...

And could that confusion have prevented reconsolidation at some location? {this is getting pretty deep into speculation}