An acquisition is the moment when every part of a credit file gets tested at once. The target has to be diligenced, the structure has to work for a lender who was not in the room during negotiation, and the whole thing has to close on a timetable set by a seller who has other options.
Most deals that fail late do not fail on price. They fail on a working capital mechanism nobody modelled, earnings that did not survive diligence, or a capital structure that could not absorb the gap between what the buyer had and what the deal needed.
This is the sequence a middle-market buyer actually moves through, and the places where deals reliably come apart.