The first words of Chapter 3.IV state that Le Chapelier gave André-Louis the news of his godfather's move to Meudon "later in the week", the week in early August 1789 in which André-Louis went to visit Le Chapelier.  This is clearly a typo; there is a ten-month gap between Chapter 3.III and Chapter 3.IV.

Consider: In the meeting of Chapter 3.III it was "less than a year" since Le Chapelier yielded to André-Louis, confirming 1789 as the year of that meeting.  But in 3.IV, André-Louis has been a swordsman for "a year and more", placing this chapter in 1790.  Moreover, having received the news, André-Louis goes to Meudon "at the very first moment", where his godfather notes that they haven't met for "two years".  Finally, the meeting in Meudon is in two places declared to be in June!