The Constitution is the supreme law of the land. The IEC must obey the dictates of the Constitution.
Section 96 states:
“There shall be a general election of all the members of the National Assembly which shall be held four months after the date of election of office of the President.”
Hence the elections must be held exactly four months after the election, no more no less. This is the arithmetic of the law.
When the law intends to be flexible it says ‘within a given period’. When it intends to fix a date, it gives a reference date and an exact date from the reference date for a given act to happen. When it does so it makes it mandatory for the event to fall on that date.