Yes — if you mean muhurti-sahit paccakhkhan or a full-day vow, then it is taken for the whole day according to the vow’s rule, and it is not dependent on Navkārshi or Chauvihar timing unless that specific paccakhkhan itself mentions those rules.

Simple way to understand it:

• Navkārshi and Chauvihar are food/drink timing disciplines.
• A full-day paccakhkhan is a vow for the entire day.
• So once taken properly, it remains valid for the whole day until the vow ends.

But one important point:

• The exact wording and type of paccakhkhan matter.
• If it is a vow related to eating, drinking, or certain restrictions, then it must be followed exactly as prescribed.
• If there is any doubt in the wording, it is best to take it from a qualified Jain upādhyāy/muni or knowledgeable person.

In short: Yes, a proper full-day paccakhkhan stays for the whole day, irrespective of Navkārshi or Chauvihar, unless the vow itself is time-bound.