Explanation for one of the Inception FAQ's

Rating: 10/10 (21 December 2011)

I was reading through the Inception FAQ's and came across this question: "Was the end a dream or reality?"
The answer held a lot of amazing explanations and two theories: the ending was reality or the ending was a dream. At the end of the explanation for the 'ending being a dream', the text says: "Also: This may be a continuity error, but when Arthur comes to get Cobb in Tokyo, they leave the hotel room and go to the roof for the helicopter at night. When they're on the roof, it's day."
I just wanted to point out that at the time Arthur comes to pick up Cobb, it's pitch black, and when they're on the roof, it's brighter, as a result of a new day. Meaning, the sun is about to come up, that's why it's day by the time they reach the rooftop. For example, Cobb and Arthur could've been awake at like 4:30-5:00 AM at the time he's talking to his kids (plus, his kids could only call him during the afternoon in Los Angeles, where his kids live, due to the time zone) and by the time they reach the rooftop, it's like 5:30-6:00 AM, indicating the arrival of dawn.
I wanted to edit my idea/theory into the FAQ, but I didn't want to pay with my credit card, so I thought I'd just write it here :) What are your thoughts?! O: