Three of my smart phone shops came back because one of the pick boxes was unchecked. Weird. I checked my copy and it was checked on the original. I did receive a 10.
I received comments that the promotional display was not shown. The particular mobile phone company usually does not have promotional advertising at the displays anymore. Hard to decide if the phones are on a specially branded display (Brand name only in identical signs to other brands). However in this case, there was a sandwich board promotion on the other side of the store. From my report, I marked 0 customers. Taking the display photo without being detected was a one time opportunity.
I emailed the grader about the circumstances and received a nice reply. I figured it might help in the future.
Do not read so much, look about you and think of what you see there.
Richard Feynman-- letter to Ashok Arora, 4 January 1967, published in Perfectly Reasonable Deviations from the Beaten Track (2005) p. 230