Question about Spanish MFA phones

[libertyh]

Hi all,
Thanks so much for providing this tool! We have been using the Spanish MFA to create word and phone textgrids for a project, and I had a question about the choice of phones. The voiceless palatal fricative ç is used for the sound for "j" and "g" in jengibre (ginger) as well as the "j" in "mujer". However, we have found that it is more typical in Spanish IPA to see the voiceless velar fricative x for this sound, see also here. Is there a particular reason for the choice of the phoneset for the Spanish MFA so we can understand this?
Thank you!
Liberty