Global fields retain the last value they held when the database was last closed on a local client. Those values are restored each time a new client opens the database. Hence, you have three options:
1) Close the database on the server, open it locally using Pro / Advanced. Set the fields, then rehost.
2) Create a set of parallel "normal" (non-global) fields. Use scripting to set the globals whenever someone opens the database to the values in the non-global fields.
3) Use scripting to set the values directly (store the defaults in the script instead of in fields).
Advantage of option 2: You can change the defaults merely by changing data in a table. 1 requires shutting down the database; 3 requires a code change. 2 does carry extra schema load.
Each choice therefore carries different benefits / costs.
I used method 2 ... It's working well !