XigmaNAS

under #2 in the console setup and/or in the GUI an option to switch
from the current DHCP address to a static form of the same address.

once DHCP works hit the button and "presto" it is static.

or is that what the save button does under LAN management
or is that just for the GUI

Generally it is bad practice to have a static IP address in the middle of a DHCP scope. Making it easy to perform bad practice is probably a bad idea.

ok that is reasonable