App worked flawlessly but using it at SFO problematic

App worked fine but staff at SFO did not seem to be up to speed on the process. Did skip long queue to reach passport control but then was verbally asked all the questions in the form plus more detailed ones. Needed to scan the receipt twice: once at the passport control and again when leaving the baggage area. It was not clearly marked where to go and what to do at each stage. Process could be streamlined further.

Viroco about Mobile Passport by Airside