The one-line version: Billing Period divides the dates into chunks — in batch, it cuts one invoice per chunk; in Generate (for a reservation without a Rate Frequency) it sets how many lines the invoice is split into. Either way, it changes how things are divided, never the total. Line Grouping then controls how the billed periods are combined into invoice lines — never changing the total.

All amounts in dollars. Canonical basis: $3,100.00/month = $100.00/day in a 31-day month.

Three similarly-named reservation settings do completely different things:

Billing Period breaks the billed dates into chunks (Calendar month — the default — 7 days, 14 days, Calendar week, or Anniversary month). Each flow uses those chunks differently:

So for an ordinary reservation (no Rate Frequency), Billing Period does change the Generate lines — it carves the dates into more or fewer lines. It never changes the total, only how many lines there are and what dates they span.

Same $2,100.00 either way; Billing Period changed the number and dates of the lines, not the money. A stay spanning two months on Calendar month splits into one line per month — that per-month split is the default, and it's what makes Line Grouping a no-op for ordinary fees (§4).

Billing Period always has a value. New reservations default to Calendar month, and the dropdown has no "None" option — so from the reservation screen, a period is always set.

For a reservation with a Rate Frequency, Generate stops dividing by the Billing Period: the rate lines come from the Rate Frequency instead (trimmed to the chosen dates). So the Generate preview is the same, whatever the Billing Period is (Calendar month, 7, 14, or 30 days).

$700.00 × 4 = $2,800.00 — the same Generate preview for any Billing Period (Calendar month / 7 / 14 / 30)

The lines never overlap and never share a day. For these reservations, Billing Period only affects the batch invoice schedule (§3) — not the Generate lines.

Why the difference? A reservation with a Rate Frequency already breaks the stay into rate periods that fit together perfectly with no gaps; dividing again by Billing Period would cut them up and risk billing the same day twice. An ordinary reservation has no such rate periods, so Billing Period is what divides its dates into lines.

In a batch, each chunk becomes its own invoice. For the weekly-Rate-Frequency stay above:

The total across the invoices is the same ($2,800.00); only the number of invoices and their dates change. See "Managing the Batch Invoice Workflow in DoorSpot" for how batch invoicing processes reservations end to end.

Separately from the invoice schedule, Line Grouping decides how billed periods are combined into invoice lines. It's set in Settings > Accounting, with separate choices for manual generation and for automatic batch:

The two flows default differently on purpose. Out of the box, a Generate invoice shows one row per fee (a tidy per-tenant invoice), while a batch invoice shows one row per month (clean month-by-month revenue). A client can change either one on its own; the money is identical either way. If a manual and an automatic invoice for the same reservation look shaped differently, this is usually why.

Grouping only changes the layout when there are same-rate periods that cross a calendar month and nothing has already split them by month. In practice that means a Rate Frequency reservation — it ignores Billing Period (§2), so its cycles run straight across the month boundary and grouping is the only thing that reshapes them.

Reservation Jul 1 → Aug 25, rate fee $3,100/month, Rate Frequency = Weekly, Billing Period = Calendar month — eight even 7-day weeks at $700.00. Same $5,600.00 total, different shaping:

An ordinary fee usually shows no difference. For a reservation without a Rate Frequency, the Billing Period (Calendar month by default) has already split each month into its own chunk (§1), so one-row-per-fee and one-row-per-month produce the same lines. Grouping visibly changes the shape only for a Rate Frequency reservation like the one above (where same-rate cycles cross a month that no Period has split).

Grouping never changes the total or which days are billed. Lines with different amounts are always kept separate — only side-by-side lines at the same rate get combined.

One row per month keeps revenue cleanly tied to a calendar month (handy for month-end books). One row per fee makes a tidier invoice for the tenant (one line per fee for the whole stay). Because the two only differ in presentation, a client can pick whichever suits their books for Generate and, separately, for batch — the money is identical either way.

"I changed the Billing Period, and my Generate preview split into more (or fewer) lines."
→ Expected for a reservation without a Rate Frequency — Billing Period carves the dates into lines (§1). The total is unchanged; only the number of lines is.

"I changed the Billing Period, and the Generate preview didn't change at all."
→ Expected for a reservation with a Rate Frequency — those ignore Billing Period; the rate lines come from the Rate Frequency (§2). For the batch, the Billing Period does affect the batch invoice schedule.

"Batch cut more invoices than Generate showed."
→ Expected — batch cuts one invoice per Billing Period (§3); Generate previews for a single date range. Totals match.

"I switched one row per fee vs per month, and nothing changed."
→ Expected for an ordinary fee: the Billing Period has already split the months, so the two look the same. Grouping visibly differs only for a Rate Frequency reservation whose cycles cross a month (§4).

"One row per month vs per fee changed my invoice total."
→ It shouldn't. Grouping never changes totals or billed days (§4). If a total moved, something else changed (a rate, the dates, or proration).