The behavior you’re seeing is expected. The usage percentage shown in the editor refreshes periodically, not in real-time, and it displays a rounded whole number. Because of that, small increments from individual requests are invisible until they accumulate past the next rounding boundary, which creates the “stays flat, then jumps” pattern you’re describing.
For more granular and up-to-date usage tracking, check your dashboard — it shows a detailed breakdown of individual requests and token costs.
Other users have reported the same observation in this thread, and the recommendation is the same: use the dashboard as your source of truth for usage tracking.
For reference: Usage and limits