The logic behind this is that if you take the lead at this stage, your opponent only has a limited time to catch up. This is also true in chess, although I suspect it is easier to blow a lead in chess than it is in football. In a nine round event Game 7 can often be the key game (especially in a large field) where a win on the top board puts a player out in front, and every one else scrambling to catch up. It is often the last round where the closest challengers play, leaving the leader with a slightly easier set of games to finish.
This was certainly the case in this years Doeberl Cup when James Morris sat down against GM Hrant Melkumyan. By winning this game Morris took a clear lead in the tournament, and pulled ahead of the top seeds. Having played most of them already, he had a slightly easier run home, and the 1.5/2 finish was enough for outright first.
Melkumyan,Hrant - Morris,James [E07]
O2C Doeberl Cup Open Canberra (7.1), 27.03.2016