METERING · FICTIONAL INVOICE INSPECTION
Seat billing: quantity and effective date
Follow individual meter records into invoice lines, one credit application and a separate collection/refund ledger.
Scroll the diagram left or right to inspect every label.
Your experiment
Hold the unit seat price constant and vary initial quantity, new quantity and change day. Reconcile the initial charge with the separate proration line.
Each observed ledger event takes three inspection seconds. The actual fictional event day is shown on the board. Invoice amounts are frozen at finalization even when later usage arrives.
Finalized invoice lines
| Line | Billable units | Amount |
|---|
Recent ledger events
Offline accounting mechanics with synthetic records and fictional CU rates—not a Stripe integration, Gemini price quote, real invoice, tax calculation or financial advice. Rates are integer minor units per 1,000 metered units. Each usage line and seat proration is rounded to the nearest minor unit, ties away from zero. The period is exactly 30 days; proration uses remaining days. Free input/output allowances are separate. Credits offset the finalized gross once; excess carries forward. Late events are held for another invoice, not billed here. Retry delays are fixed exponential days and create no new invoice. Refunds are separate entries bounded by collected cash and do not reopen the original invoice in this model. No tax, currency conversion, discounts, disputes, partial payments, provider fees or legal billing requirements are modeled. Metering concepts · Proration concepts.
Compute seat proration within one fictional invoice
A thirty-day period bills initial seats for the month plus a prorated change for the remaining days. Initial seats two, changed seats four, price one thousand minor units and change day fifteen produce a two-thousand initial line and a one-thousand adjustment. Changing to one seat instead produces a negative five-hundred adjustment. One hundred minor units equal one fictional currency unit. This arithmetic is a declared teaching policy, not a vendor price, financial recommendation or real charge.
Set seat and usage inputs
Include seat subscription enables Initial seats, Seats after change, Monthly seat price and Change day. Turning it off removes both seat lines and disables their inputs. Fixture tenant selects whose usage is billed. Usage quantity multiplier scales meter quantities. Free input and output units are allowances; input and output rates price the remaining units per thousand. Include duplicate event adds a repeated team-a event; Deduplicate tenant plus event ID prevents counting it twice. It has no relevant repeated event for team-b.
Understand finalization and collection
Days of grace closes the period at day thirty plus grace. Events arriving later are deferred and do not revise the invoice. Customer credit is applied once, up to the gross amount. First N attempts fail and Maximum collection attempts determine whether collection eventually succeeds or remains past due. Requested refund creates a separate refund only when it does not exceed collected cash. These controls affect collection, not the seat proration formula. Rounding uses nearest minor unit with ties away from zero for the prorated change.
Run a seat-only comparison
Keep subscription enabled, set usage rates to zero and customer credit to zero, then inspect the completed invoice. The default seat inputs yield thirty fictional units. Move change day to zero for forty units or day thirty for twenty. Set new seats equal to initial seats to make the adjustment zero at any change day. Disable the subscription as well and the invoice has no charge. A requested positive refund then fails because no cash was collected.
Inspect the event ledger
Usage, Seats and Collection tabs only choose which controls are visible; they do not create separate invoices. Play and Pause reveal ledger events, Next ledger event advances, Restart rewinds, Speed changes pace and Inspection time seeks. Export fictional invoice JSON downloads the entire computed fixture, including configuration and final state, regardless of the currently viewed step. The inspection lasts three seconds per event and is not a simulated calendar clock. There are no taxes, exchange rates, payment providers, real subscriptions or next-period invoice processing. Read line amounts and retained receipts rather than inferring billing policy from animation speed.