Depuis and the subjective.

Writing challenge c1 camping:  Although she had already been camping in this forest for a week. 
Bien qu 'elle campe déjà dans cette forêt depuis une semaine.

I understand that bien que triggers the subjective and confirming my assumption that campe is used because she was still camping at the time, but not sure why the subjective passé is also right. Does already effect the tense in this case.