Set up recurring revenue schedules

I need to create the recurring revenue schedules for three clients so the quarter closes cleanly. For ACME Corp, set monthly invoicing starting July 1 at $12,000 for 12 months; for Meridian LLC, set quarterly billing starting August 15 at $45,000 for four quarters; for Brightwave Inc., set annual renewal on September 30 at $180,000 with a 30-day renewal notice. Make sure revenue start and end dates match the contracts and that schedules tie to the opportunity records; check for overlapping schedules and notify me of any proration applied before I activate them.

Before I push these recurring schedules live, make approving them painless for the finance reviewer. Show the total ARR and next 12‑month cash flow at the top, surface any proration adjustments and the contract clause that requires quarterly billing for Meridian LLC, and highlight if any schedule dates will create duplicate invoices for July–September. Flag assumptions about tax or currency that would make a reviewer hesitate.

I uploaded three contract line items; the opportunity shows two monthly schedules for ACME starting July 1. I fear I'll double-bill the client if I activate both. I can't tell whether the duplicate came from the CSV import or an earlier manual schedule. What is the most likely cause and the fastest safe fix that preserves audit trail and avoids missing July revenue?

This keeps happening every quarter: I import contract lines or edit an opportunity and end up with overlapping recurring schedules, then I lose time finding and reconciling the duplicates. Which habitual changes will stop this — what three checks should I run before activation, and what small conventions (naming, single source for contract lines, a pre-activation checklist) will prevent duplicates while keeping auditability?