Could one say that Hashem chose to speak to Moshe via a daber or omar mode of speech in response to Moshe’s state of mind?
For example the Mitzvah of Tzitzis is just after the Shabbos breaker is executed. After Moshe sins at the rock it says omer as Moshe was probably petrified. Bemidbar 16:20 is interesting. Initially Moshe was taken aback by Korach’s rebellion. By now he understood what was necessary and could receive a daber communication.
It is possible, but we have to consider that the order of the topics was not nessessarily written in a time order.