I agree that there is no standard answer here. For example, SeeLevelhx uses the 'don't shop before' while clearly requiring the shops be performed only on the date assigned. Unless your instructions or guidelines are clear as to a date range or specific date, assume the shop is date specific.
My posts are solely based on my opinions and for my entertainment, contact a professional if you need real advice.
When you get in debt you become a slave. - Andrew Jackson