Barring evidence to the contrary (internal emails/discussion), I definitely would assume mistake over malice.

I've worked in Monetization at 3 SaaS cos (admittedly all smaller than Uber, O(100-1000) employees), and at all of them I've seen mistakes of a similar proportion of revenue (~1%) made in both directions (overcharging and undercharging customers) in violation of the letter of our contracts with absolutely zero intent or malice.

Wage law adds several additional layers of complexity beyond that.