Service Level calc from /api/v2/analytics/queues/realtime/intervals

Trying to calculate Service Level % using the raw interval data from the realtime API. I’m summing handledCount and responseTime but the math feels off compared to the dashboard. Here is the payload structure I’m parsing. Am I supposed to filter by offerCount or just look at handledCount? The responseTime seems to be in milliseconds. Not sure if I’m dividing correctly.