Lotus what do you mean by :-

This happens quite often for modern Mauritian stamps, as certain
values are produced in much smaller quantities than the internal value
rate (usually the first stamp of each series),


Do you mean that the lowest face value of Mauritius stamps in a set is
worth more in used condition than the actual face value in mint
condition because the mintage is lower than other larger countries
abroad?
Even though Mauritius Postoffice issues less in quantity than most
other larger countries, it`s lowest face value of commemorative stamps
is still between 500 000 to 2 000 000, for definitive stamps the
quantity will probably be higher.