Does Oracle EPM patch update affect existing out of box form definition?

Summary:

We have configured Financials module for the client. We are tweaking out of box created Forms and Dashboards, to suit client needs. For e.g. instead of existing/created OFS_Net Income member in forms rows definition, we have changed it Surplus /Deficit (client specific Net Income member in client's Account hierarchy) OR say removed some columns or added new columns into out-of-box created forms.

Question - Can Oracle patch updates change the definition of Out-of-box forms in the above configured Financials module, so that the form definition changes made by development team could be undone or messed up. Logically, I don't this Oracle updates will change the definition of modified out-of-box forms in configured Financials module, though the new features would be available. Please can someone provide a confirmed answer on this. Also, if you could provide the source url of the information; that will be helpful.