That presumes that they'd be able to get the same fare numbers during those additional 4 hours. I can see 11pm-3am being a fairly high-demand time. Not sure if there's an equivalent time slot with similar demand.
According to this NYC stats sheet (page 8), there's a sharp drop off after 12. 8 AM -> 11 PM is better most days. Although, who knows, maybe Lyft has some special pricing.
