Regarding AP and PA data in dwifslpreproc

Hi, I have a question about the AP and PA data in dwifslpreproc.
The MRtrix3 commands are very easy to use and I always rely on them.

I am imaging DWI with 30 axes of phase encoded AP and 31 axes of PA.
The diffusion gradient is applied in different axes.

Should the AP and PA axes be the same in dwifslpreproc?

I would be very happy to learn more about it.
Thank you in advance.