Graduated pricing
Graduated pricing is how the Syndik8 paid plan is charged: each unit is priced at its own rate, the way income tax charges each slice of income at its own band. The first aircraft costs £20 a month and every aircraft after it £12, so a fleet never re-prices because it crossed a threshold, and adding an aircraft always raises the bill by exactly the advertised amount.
Members are charged the same way, with the first band free: the first 15 members are included, and each member beyond that costs £1 a month. The allowance is flat rather than per aircraft. All figures are ex-VAT; 20% is added on top and itemised on the invoice.
Contrast this with volume pricing, where crossing a threshold re-prices everything you already have. Under volume, a second aircraft could cost less than the first one did, and the discount would be applied backwards to capacity already paid for. Graduated matches how the price reads out loud.
Subscribing early can qualify a syndicate for founding pricing, which discounts the whole subscription.