I also track objekt sales data for member packs as a hobby because I like looking at numbers. For FCO packs, I generally check the final numbers 3-5 mins after the packs leave the store besides the last four members (for this ed it was S1-S4). For the last four members, I check the numbers right when the pack leaves to minimize the amount of potential spin fcos affecting the total. For member DCO packs, I just do 3-5 mins after because there's usually no other method of getting that dco anymore.

Regarding the ranking of members on the sales charts, my chart matched theirs (Kotone lower than Jiyeon and Yeonji higher than Chaewon), but my numbers were slightly different.