As I wrote: "ear"witness accounts are highly unreliable, yet here's another witness from NorthJersey.com:
Fair Lawn resident Michelle Samolis told WCBS-TV news that she heard eight to 10 popping noises around the time the officers were shot.
In a rapid-fire situation, it is very difficult to estimate the number of shots fired, even by an expert let alone a disinterested bystander.
Also, if the cops and the bad guys happened to fire a round simultaneously it would sound like one shot.