Every hour the blockchain takes the median of the witness price feed inputs. After 3.5 days, it takes the median of those hourly samples (over the entire 3.5 day period).
So, yes it is more difficult to disrupt the price over that entire period, but the resulting payment may be more or less than $1.
Unfortunately the state of documentation on the Steem platform is not the greatest and there have been many rounds of changes and adjustments, not all reflected in documents, which in any case are often not complete. Unless you can work it out from the code itself, often the only way to find out how the system works is to ask someone who is familiar with the history and current rule set. Not an ideal answer, but it is the best I can offer.