What is the precedence of execution of Order Management Extensions (On Save/On Start of Submission)

Hello experts,

We have both On Save and On Start of Submission of Extensions for Oracle Fusion.

We are defaulting Subinventory of the order line when it is blank using different On Save and On Submit Extensions.

In our current production, we noticed that On Start of Submission is being called first, where are recently we observed that in one of our test instance we are seeing that On Save is being called.

Is there any precedence of execution On Save and On Start of Submission extensions. Can you manage the precedence of execution of these extensions.

Thanks

Dharma