Bollinge has misunderstood and not given you a correct response.
Your PSA of 0.3 indicates that the surgeon was not able to remove all the cancer - some stray cells are probably still hanging around where the seminal vesicles were. There is no need to do another PSA test earlier than the 3 months; the specialist is looking for whether it falls, rises or stays the same as this helps him to know where the cancer cells are.
You are not in danger though and there is no urgency - best to recover a bit more from the op and then have more treatment if it is needed. Stage 3 just means that rather than the cancer being fully contained, it had already spread a little bit outside the prostate (in your case to the seminal vesicles). You were also correct to write that your final pathology was high risk - that is determined by your G(4+3) plus seminal vesicle involvement.
I wouldn’t be too surprised that the surgeon seemed a bit reluctant to talk about it - I imagine most surgeons are very disappointed when it turns out that the op was not wholly successful, particularly as they have to publish their stats.