When does Mortar Section Leader KD time start being credited?

I'm trying to understand how KD time is credited and could use some assistance. I was pinned SGT May 1st 2019, My first NCOER has me rated as the Section Leader from that day to my thru date of April 30th 2020. I was pinned SSG June 1st 2020. Does my KD time start when I started being rated as Section Leader back when I was pinned SGT last year or does my KD time start when I was pinned SSG this year? I've been told different things from various people and am trying to get some confirmation. I'm stuck at a crossroad where I have to choose to advance my career or try to get a different assignment in order to help my daughter who has autism get the help she needs in school due to a terrible school district at my current duty station. If my KD time started when I took over the Section I can hold out a bit longer to finish it but if I have to wait until 2022 to finish my KD time I'm going to have to move somewhere else in order to provide for my family.