Missing settings when upgrading from v1.90 to v4.20

4 weeks ago
I have upgraded the database all the way from v1.90 to v4.20 and all seems good except that some setttings are missing from the Setting table.  

For example, I want to set ShoppingCartSettings.RoundPricesDuringCalculation but it is not in All Settings nor in the Setting table in the database.

Does anyone have suggestions as to why this is the case?
Many thanks.
4 days ago
I just added the missing setting and everything works fine.  I had expected the upgrade process to do it but it didn't.