Under the example values (10 million free tokens, 45,000 tokens per PR, 40 PRs per month, 24 hours saved per month, $85 per hour, 60 exit hours, 10 hours of residual monthly overhead), the runway is about 5.6 months, the net savings are about $1,190 per month, the break-even is about 4.3 months, and the reversal threshold is about 78 exit hours.