HUGE apologies for this, folks. I had double, triple, quadruple-checked the math so many times that I stupidly neglected to verify the Al stuff to the same degree.
364 is indeed the correct answer, so Stephen still has the immunity pass.
The person who possesses the hidden idol will be informed shortly...again, assuming someone found it.

Sorry again, guys--this was a relatively last-minute competition and I can assure you that everything else will be held to a much higher standard before I post it.