On the roof, the boys eat candy bars. Dewey's goes from fully wrapped then has no wrapper then it does.
At night on the roof Malcolm lies on his back empty handed. When he sits up he is holding a candy bar.
On the roof the boys eat "...the last candy bars of your childhood." In daylight. At night when in talks with Lois the boys have more candy bars.
Stunt Performer visible when Malcolm is on the roof.
When the porshe pulls up to the house you can see the camera crane reflected in the windshield.