The largest leak in most service businesses, and the only one with no instrumentation. Your phone provider can give you the first two numbers as a standard report.
Recovered calls are conservatively assumed to convert at 75% of your live-answer rate, not 100% — a caller reaching an AI agent at 8pm converts well, but not as well as a human at 2pm. Voice agent running cost of roughly $0.19/minute at a 3-minute average is subtracted.