Clarification: activeCpuUsageMs exceeds duration for a one-vCPU session #356

Using @vercel/sandbox 3.5.0, a stopped nonpersistent session configured for one vCPU and 2048 MiB returned:

• currentSession().activeCpuUsageMs: 3610
• currentSession().duration: 3131

The installed SDK describes duration as wall-clock milliseconds and passes both values through without a unit conversion.

Can active CPU legitimately exceed wall-clock duration multiplied by allocated vCPUs? Do these fields use different measurement intervals (for example, startup or shutdown)? Which documented value or bound should prepaid accounting use? Can authoritative final usage be recovered after sandbox deletion?

This is an observed result, not a reproducible SDK defect claim. We have retained the charge as unknown rather than clamp either measurement or manufacture a settlement.