I don't know your application, so I can only make speculations. Nor do I know why think you actually think this is a problem. That is, my assumption is that someone has reported a performance problem.

Keep in mind that even if the stored procedure is a single INSERT statement, the procedure may be called repeatedly.

And please observe that I don't anything - it is just that I have seen bad application patterns before.

And, of course, if this a third-party application there is not much you can do but bug the vendor.