Deciding what to do when providers have such different protocols?

I agree with @jeffmarc that it's possible Mayo either didn't understand that you already had a proctectomy and/or also didn't understand that Mayo did the proctectomy. I could be wrong, but I thought Mayo's policy was that since they did the primary treatment (ie. RP) you're now a permanent patient of theirs. I'd reach out directly to them for an appointment as an existing patient. Then, if they still won't see you, or if you're just so inclined, I'd go for a second (or third) opinion to another CCOE if that's an option for you. Best wishes.

That is a big jump. I would want to be tested in three months and not wait six months. The doubling rate is the most critical number, It really is necessary to see what the next number is to know what the doubling rate actually is.

If you don’t get salvage radiation soon after you hit .2 it can cause your cancer to be more aggressive. There’s a lot of opinions about this, But ASCO is pretty definitive about this, and they set the guidelines.

Here’s what they have to say about Having your PSA rise too much

From Ascopubs about what PSA to do salvage radiation.
≤0.2 ng/mL:
Starting at this level maximizes disease control and long-term survival. Patients treated at PSA < 0.2 ng/mL achieve higher rates of undetectable post-SRT PSA (56-70%) and improved 5-year progression-free survival (62.7-75%).
Delaying SRT beyond PSA ≥0.25 ng/mL increases mortality risk by ~50%.

0.2–0.5 ng/mL:
Still effective, particularly for patients with low-risk features (e.g., Gleason ≤7, slow PSA doubling time). The Journal of Clinical Oncology recommends SRT before PSA exceeds 0.25 ng/mL to preserve curative potential.

0.5–1.0 ng/mL:
Salvage radiation remains beneficial but may require combining with androgen deprivation therapy (ADT) for higher-risk cases.

If you can find your Mayo patient number, have it in hand when you call to remind Urology that you are an existing patient who had surgery at Mayo. They will be able to pull up your Mayo records using your Mayo patient number. If you can't find your Mayo patient number, tell them your surgery date and who did what to you. NOTE: I found out the hard way that Mayo classifies you as a new patient if you haven't been there in three years. But you can still be seen after they follow their procedures for reinstating a past patient. Good luck!