Using "mentioned above" when speaking

Is it valid to say "mentioned above" when one reference to something one have previously said?

Context example (transcript from The Law of One):

Questioner: George Van Tassel built a machine in our western desert called an “Integratron.” Will this machine work for that purpose, of increasing the life span?

Ra: I am Ra. The machine is incomplete and will not function for the above-mentioned purpose.

Solution 1:

"Above-mentioned" wouldn't be a good chose nor very clear because the listener would be wondering "above what?" "above where?".

For your example, you could use aforementioned:

Ra: I am Ra. The machine is incomplete and will not function for the aforementioned purpose.

Per MWO:

aforementioned: mentioned previously

Solution 2:

Mentioned above is a more typical phrase in writing than it would be in speaking. In speech, I would expect to hear as I said previously or as previously mentioned, or something similar.

Solution 3:

No, that's acceptable in writing. When you are giving a lecture or making a speech, you'd better say something like:

• "As I have already mentioned."
• "As I have mentioned before."
• "As I have mentioned previously."

"The machine is incomplete and will not function for the purpose I have just mentioned/for that purpose/for that specific purpose/for the purpose I mentioned earlier."