Thanks Paul for the detailed check and answer. Indeed I also get the same results and they are correct to me too. My problem is that the analisys team of my project (which use SPM) tell me that they can't run group analysis because they get the following error in DTI group statistics:

------------------------------------------------------------------------
Running job #1
------------------------------------------------------------------------
Running 'Factorial design specification'
Mapping files :
** The images do not all have same orientation and/or voxel sizes. **
The function assumes that a voxel in one image corresponds exactly
with the same voxel in another. This is not a safe assumption if
the orientation information in the headers or .mat files says that
the images are oriented differently. Please ensure that you process
all data correctly. For example, you may have realigned the images,
but not actually resliced them to be in voxel-wise alignment.
Here are the orientation matrices of the image volumes. This list
can be used to determine which file(s) are causing the problem.

[-1.5 0 0 96.2498; 0 -1.5 0 101.251; 0 0 1.5 -74.2508] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/312/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2507; 0 -1.5 0 101.251; 0 0 1.5 -74.2504] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/59229/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2499; 0 -1.5 0 101.251; 0 0 1.5 -74.251] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/2604/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.25; 0 -1.5 0 101.25; 0 0 1.5 -74.2512] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/69420/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2501; 0 -1.5 0 101.25; 0 0 1.5 -74.2513] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/2972/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2504; 0 -1.5 0 101.251; 0 0 1.5 -74.2511] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/19100/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.251; 0 -1.5 0 101.25; 0 0 1.5 -74.2506] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/19971/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2502; 0 -1.5 0 101.25; 0 0 1.5 -74.2509] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/11336/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2497; 0 -1.5 0 101.25; 0 0 1.5 -74.25] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/39802/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2515; 0 -1.5 0 101.251; 0 0 1.5 -74.2499] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/11290/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2498; 0 -1.5 0 101.25; 0 0 1.5 -74.2499] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/31146/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2495; 0 -1.5 0 101.251; 0 0 1.5 -74.2512] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/22266/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2513; 0 -1.5 0 101.25; 0 0 1.5 -74.2514] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/35175/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2498; 0 -1.5 0 101.25; 0 0 1.5 -74.251] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/43442/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2508; 0 -1.5 0 101.251; 0 0 1.5 -74.2509] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/777/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2501; 0 -1.5 0 101.251; 0 0 1.5 -74.2508] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/44076/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2495; 0 -1.5 0 101.251; 0 0 1.5 -74.25] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/33920/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2516; 0 -1.5 0 101.251; 0 0 1.5 -74.2502] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/60497/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2497; 0 -1.5 0 101.251; 0 0 1.5 -74.2507] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/3910/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2496; 0 -1.5 0 101.251; 0 0 1.5 -74.2498] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/13746/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2502; 0 -1.5 0 101.25; 0 0 1.5 -74.2509] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/38697/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2503; 0 -1.5 0 101.25; 0 0 1.5 -74.2502] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/69124/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2507; 0 -1.5 0 101.25; 0 0 1.5 -74.2492] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/17850/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2502; 0 -1.5 0 101.25; 0 0 1.5 -74.2501] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/24095/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2505; 0 -1.5 0 101.251; 0 0 1.5 -74.2501] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/52379/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.25; 0 -1.5 0 101.25; 0 0 1.5 -74.2504] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/54612/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.25; 0 -1.5 0 101.251; 0 0 1.5 -74.2494] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/30763/gc_DIFFPREP14/dt_FA.nii
[-1.5 0 0 96.2504; 0 -1.5 0 101.251; 0 0 1.5 -74.2504] /home/Data_ss/NAS_wp3/20-Dec-2017/Data/38846/gc_DIFFPREP14/dt_FA.nii

Failed 'Factorial design specification'
Error using spm_check_orientations (line 65)
The orientations etc must be identical for this procedure.
In file "/home/wp3/spm12_v6685_cat12_r1207/spm_check_orientations.m" (v5097), function "spm_check_orientations" at line 65.
In file "/home/wp3/spm12_v6685_cat12_r1207/config/spm_run_factorial_design.m" (v6219), function "spm_run_factorial_design" at line 677.

No executable modules, but still unresolved dependencies or incomplete module inputs.
The following modules did not run:
Failed: Factorial design specification
======END======================

and they get this error only if dt_FA.nii are generated by fat_proc_dwi_to_dt with -mask* option, i.e. all matrix origins are veeery little different (0.00xx), while with fsl dtifit, tortoise EstimateTensorWLLS and even with fat_proc_dwi_to_dt with Automask the matrix is the same for all images FA images of all subjects:
Geometry String: "MATRIX(1.5,0,0,-94.75,0,1.5,0,-99.75,0,0,1.5,-72.75):128,157,115"
Probably the problem is in the SPM side, but we have not found a solution for our data yet.
Cheers,
Giuseppe