AWS Billing Conductor

TL;DR: Consolidated billing tells you what AWS charged you; Billing Conductor tells you what to charge someone else. It sits between your Org's real bill and the pro-forma invoices you generate for internal or external customers — applying markups, custom rates, and custom line items — while the real AWS bill is unchanged. Critically, it doesn't save money; it redistributes it on paper. It's the right tool for MSPs issuing customer invoices and enterprises doing custom-rate chargeback, and overkill for nearly everyone else.

The numbers

• Tool cost: ~$2 per account per month per billing-group account (min $5/account) — a 50-account Org runs $100–250/mo just to operate it, plus ongoing rule-maintenance labor.
• The core mental model: a 20% "discount" on a billing group changes only that group's pro-forma invoice — the management account still pays AWS the full real rate. Billing Conductor is an accounting tool, not a negotiation one.
• Field examples: a 12-customer MSP cut its monthly billing process from ~16 to 3 person-hours (**$3,500/mo** in labor, tool cost ~$60/mo trivial by comparison); a 200-account enterprise tried it for internal chargeback, hit ~30 hrs/mo maintenance and disputes, and rolled back to Cost Categories + tags + a showback dashboard (~4 hrs/mo).

Do this

1. Confirm you're actually in a legitimate use case first — MSP customer invoicing, enterprise chargeback with custom rates, or special currency/tax/line-item formatting. If not, stop here.
2. One billing group per customer or business unit, then attach a pricing plan (markup + rules) and custom line items (management fees, support tiers).
3. Keep Savings Plan / RI attribution deliberate — by default they share proportionally across groups; the common MSP move is to charge customers on-demand rates and keep the commitment savings as margin (set an explicit rule).
4. Reconcile pro-forma vs real every month — the delta is your intended margin or unintended config drift; investigate anything unexpected over 2%.
5. Audit monthly for orphaned accounts (new accounts default to the primary group), stale custom line items, and pricing rules that don't cover new AWS services (they silently pass through at AWS rates).

Gotchas

• No retroactive changes — a rule error caught mid-month is fixable going forward only; prior months stay wrong unless reconciled by hand.
• Free tier, Spot, and Marketplace pass through by default — free-tier math can behave oddly, and Spot/Marketplace bill at real rates unless you add explicit markup rules.
• Non-EC2 reserved capacity (RDS RIs, ElastiCache reserved nodes, Redshift RNs) each behave differently — test per service type.
• For internal chargeback, a showback dashboard usually beats formal invoicing — Billing Conductor's value is external customer billing where the invoice is the deliverable.

Skip this if

• You just need each team or BU to see their real-rate spend — use Cost Allocation Tags + AWS Cost Categories + Cost Explorer (all free).
• You need custom chargeback math but not AWS-generated invoices — Cost and Usage Reports + a spreadsheet/BI tool covers it. The tipping point for internal use is roughly $1M/yr spend across 5+ BUs; below that the rule-maintenance complexity outweighs the benefit. Its prerequisite is AWS Organizations Consolidated Billing.