MUFC said:Think about it this way, The more extra buffer of days the less suspicious for the processing agent the application looks like.
For me the only people who will have good excuse to apply with the bare minimum or with very little minimum of extra buffer are those who will be very very close to the real cut-off date when is officially published.
I thought these extra days only for people who made many trips and they are not sure about the exact dates. My opinion is these two weeks or month extra will not give you any advantages unless if you want your file looks perfect you should wait at least more than 6 months extra after you become eligible but one or two weeks will not make any difference to the processing agent.