I understand that is a logical deduction (in terms of using driving data from 10/1-10/7 for determining who gets the beta on 10/8), but I wouldn't rely on it. I believe Elon's initial statement (about needing 7 days to observe driving behavior) was based on his impression at that time as to the expected software release schedule. However, now that the schedule has been pushed back a week, it would not surprise me at all for that 7-day evaluation to become 14 days.
I actually expect Tesla to use the 14-day period for determining who is worthy of receiving FSD beta. It doesn't really make sense to wholly ignore valid data on an individual's driving behavior; and, most importantly, using the 14-day window will lower the number of people who, in theory, should be among the first group to receive the software.