In a sign that freewheeling, well-funded Bay Area startups are becoming more cost-conscious, the on-demand grocery delivery service Instacart recently told its couriers that it would be cutting pay rates by as much as 63 percent.

According to the Wall Street Journal, San Francisco drivers who pick up bags at grocery stores, for example, will make $1.50 per drop-off rather than the previous $4. Instacart has also made a 50 percent cut, down to $0.25, on the commission that it pays per item to drivers when they are shopping in-store.

"After these changes our shoppers will earn, on average, an effective rate of $15 to $20 per hour, which is both in line with historical levels and strongly competitive within our markets," Hyeri Kim, an Instacart spokeswoman, told Ars in a statement.

Kim would not answer Ars’ question as to why such a pay cut was necessary or even required at this particular moment.

In June, Instacart took the unusual step of allowing its delivery staff, which until then was comprised entirely of contractors, the option to become part-time workers capped at 30 hours per week.

As Ars reported at the time, Instacart spokeswoman Andrea Saul specifically denied that the 30-hour cutoff was designed to avoid providing health care to shoppers and drivers under the Affordable Care Act (ACA), where full-time employment is defined as "an employee who is employed on average at least 30 hours of service per week." The ACA, among other things, requires that employers with more than 50 employees provide health care to their workers and their families.

The startup’s own office-based full-time jobs boast "comprehensive health, dental, and vision coverage" and a "smorgasbord of food while you work, including lunch and dinner catered daily," according to company listings. In-store jobs (the overwhelming majority of the company’s workforce) only offer "$15/hr flat rate pay" and boast "flexible hours—no need to work the same schedule every week!"