Section 188.8.131.52 of the Guide to Advancement states:
A Cub Scout who has completed advancement should be congratulated immediately and publicly. And though badges of rank should be reserved for the next pack meeting, it is best to present items such as belt loops and pins soon after they have been earned. If it is possible for the pack to report and purchase these awards quickly, they could be presented at a den meeting, rather than waiting for a pack meeting. If presented at den meetings, the accompanying pocket certificates can be used in a ceremony at a subsequent pack meeting—or vice versa with the pocket certificates at a den meeting. However this is done, it is important to note that advancement is an individual process, not dependent on the work or progress of others. Awards should not be withheld for group recognition. Likewise, a youth should not be presented with recognition that was not earned simply to avoid anyone “feeling left out.”
The way Scoutbook works is once an award is on the purchase order, it is not placed on another purchase order unless it has been unapproved or the purchase order deleted. This is because once a purchase order is closed, it is assumed the item was purchased. Scoutbook is designed to follow the Guide to Advancement, thus pocket certificates should be printed when the rank is earned and purchased.