Covenants Income Question

We're a little unclear on how the wealth boon works for covenants using the Covenants book. Does the boon (250 pounds / year) add to the standard income (100 pounds / year), or does it replace it?

Thanks.

The covenant's income source gets upgraded to Greater (or Legendary), so it replaces the original value, rather than add to it. On the other hand, Secondary Income adds a second source of Typical value.