Talked to Priya about the billing migration. Her main concern is double-billing during cutover - if both systems run in parallel and both write to the same customer accounts, there's a real risk a customer gets charged twice for the same event. One option is to cut over at a known-quiet window (Sunday 3am for us). The problem is APAC. We have enterprise customers in Singapore and Sydney; Sunday at 3am Eastern is their Monday morning, the opposite of quiet. What I proposed: shadow mode for a week. The new system runs alongside the old one, sees the same inputs, produces its own outputs, but doesn't actually issue invoices. We log the diffs between old and new every day, fix whatever's diverging, and only do a hard cutover once the diffs are clean. Priya is OK with shadow mode but wants the "diff acceptable" criteria defined upfront - not after we see the diffs and start rationalizing. Fair. Next step on my plate: write up the shadow-mode plan plus the acceptance criteria for diffs. Sending Thursday.