Hey,
I think it would be correct to differ between the Netherland and the United Kingdom of the Netherlands (1815-1830).
Even though nothing changed in the coins (since the king remain the same one, and the coins never declared the issuer name), It does refer to another regime in many lands.
It can be a whole different country, or as a sub-section in Netherland, either ways it should have references to Belgium and Luxembourg, and to have same KM#'s twice, referring to different years....
The only thing that actually changed was that Belgium, Luxembourg and Limburg were no longer part of the Netherlands. Coins minted during 1815-30 continued to be minted without change after 1830, without any difference, such as this coin: https://en.numista.com/catalogue/pieces6540.html , so there is no need for this change.
If we used regime change to separate issuers or even subsections, countries with convoluted political histories like Spain and France would have to be split into dozens of sections.
