Do I need both?
On a long document, often yes, at different stages. Edit while there is still time to act on structural comments, then proofread the final version after you have made every change. Proofreading before editing wastes the proofreading, because edited sentences need checking again.
This comes up on Proofreading vs Editing, where it is answered in the context of the work itself.
Not what you asked?
Ask us the actual question
Send the draft, the rubric or the score report with it. You get a real answer and a price before you commit to anything.