It's saying that whether it affects latency or just throughput depends on how those pauses are distributed in absolute terms, not just the ratio. There's a big difference in 99th percentile latency between a 1ms pause every 400ms and a 10 second pause every 67 minutes, but they both work out to 2.5% by the ratio metric.

So yes, at the `infinitesimally small` end, time would be 'stolen' evenly from all request threads and would not be a contributing factor to the 99th percentile.