Hi, when I when I found the following government document on the web: https://data.govmu.org/dkan/sites/default/files/Municipal%20and%20Village%20Council%20Areas%20by%20District%20%26%20Description%20of%20codes_1.pdf  , I began to enter the boundaries of the Wards in the towns.
On the one hand, in this document, a clearly visible distinction is only made between District and Village Council Area boundaries: they are not coincident. 
On the other hand, the boundaries of towns and of the city (Port-Louis) have boundaries they share with VCAs. 
That is why I thought it would be wiser to shift the latter two to the same level, and then set the admin_level of the Wards to 9. 
In terms of administration, towns seem to have no more competences as VCAs. Please let me know if this is not the case.