This is getting down to semantics. If you do not enter pre-clearance before it closes, you will "miss" your connection. The problem is that you cannot know in advance exactly when pre-clearance will close on your particular day of travel. Upon request from an airline, pre-clearance can remain open past its normal closing time. From the link you posted in Post #8:

"The airline may request operations to remain open past posted hours to accommodate late transfers. CBP frequently accommodates such requests, but does not control the operations of the other stakeholders. The vast majority of passengers who use preclearance do not miss their flights. The airlines have responsibility for late arriving connecting passengers."