I've seen it for 30 days, 3 months, and so on. In fact, it doesn't matter, as long as it is handed in voluntarily, it is a good comrade! What the Commission for Discipline Inspection values is not the number of days, but the final attitude and decision of the individual.
Besides, everyone is very busy. The Commission for Discipline Inspection has other things to do, such as meetings, work and business trips. It is not uncommon to miss them.