This video was released to introduce new fans to the Flash character, prior to the release of Justice League. It restates the classic comic book origin of Barry Allen working in the crime lab at Central City Police Department, and being struck by lightning (and covered in chemicals) while working in the lab one night.
In the movie itself, while graverobbing Superman's body, Cyborg asks him if he was struck by lightning and he confirms that is the "abridged version" of the story. However earlier in the movie, when Barry visits his father Henry in prison, Henry mentions that Barry needs to get his life in order. He mentions that Barry is working "three dead-end jobs".
At the end of the movie Barry visits his father again, saying he's got "the worst job possible in a crime lab" due to the recommendation from a friend (presumably Bruce Wayne/Batman).
All of this indicates that Barry was not working in the CCPD crime lab when he was hit by lightning to gain access to the Speed Force.
Is there anything out there (director's commentary/deleted scene etc) to explain the change in origin for Barry? Or is it just a minor adjustment for the purposes of the movie?