AddOrUpdate doesn't seem to update Cron timer

I have a function which is called once when my application starts to set up recurring jobs if required (it checks the database in a table of system jobs which also stores the indentifier). If the job is required it calls the AddOrUpdate function regardless to make sure the job is there and with the most up to date settings.

The issue I am seeing is that when I changed the CRON string for my job to run every other day rather than weekly, it hasn’t updated. The Job in the dashboard still shows the old CRON timer not new one.

Any ideas?