They will credit the time as I described. They will not credit less than 70% based on limited time underway. Hiowever, they could discount the time further based on the military billet duties and their applicability to a merchahnt mariner endorsement.
A lower percentage might be used If the particular military position served in had multiople duties and only a portion related to the endorsement you’re applying for. The Marine Safety Manual notes what miltary billets are creditable, and what percentage of the time is credited. That percentage would be further reduced by 70% for time not underway as I described.
I’m sure you know. Just recalling some of the deviations from past applicants I’ve known. In years past it seemed not all USCG evaluations were done the same, perhaps that’s changed.