The volume: when the fraction matters
A fraction of a unit is not worth arguing about once. It is worth understanding once it is arithmetic: two thousand events of the same size turn the same rule into a figure with a shape of its own.
- stakes
- 1,000
- returns
- 1,000
- retained
- 60.00
- control
- 0.00
A rounding of one unit is negligible per event and not negligible in total. On two thousand invented events of the same size, a thousand stakes of 5.05 retain 50.00 and a thousand returns of 7.999999 retain 10.00, for 60.00 in all, while a control of a thousand round stakes retains nothing at all from the same turnover.
Two thousand events, one difference
The events are deliberately identical in size, so the only variable is the digits. That is what turns the page from a warning into a measurable claim.
| Line | Events | Tail each | Total |
|---|---|---|---|
| stakes of 5.05 rounded to 5.00 | 1,000 | 0.05 | 50.00 |
| returns of 7.999999 rounded to 7.99 | 1,000 | 0.01 | 10.00 |
| control: stakes of 5.00 | 1,000 | 0.00 | 0.00 |
| control: returns of 8.00 exactly | 1,000 | 0.00 | 0.00 |
| the two round-number controls | 2,000 | - | 0.00 |
How to read a figure like that without inflating it
Two cautions belong beside the number, and both are arithmetic rather than opinion. First, the 60.00 is not a charge and not a loss in the sense of money paid away: it is stake that was never placed and return that was never paid, so it does not move out of an account and does not appear on a statement. Second, the figure is proportional to turnover, not to the balance: it scales with how many times a player bets, which is why it is the same shape as any cost expressed as a percentage of turnover and why it is meaningless without stating the number of events. A reader who bets once a week and a reader who bets a thousand times a day face the same rule at wildly different scales, which is exactly what a percentage of turnover is for.
- Estimate the cost of a rounding as one unit per event and multiply by the number of events; that is the whole method.
- Do not add the stake tail and the return tail as if they were both paid: neither leaves the account, so neither is a charge.
- Compare against turnover rather than against a deposit: the figure scales with the number of bets.
- Prefer round digits if the increment divides them; on sample H that single choice moved 60.00 to nothing.
- Read the reset and expiry rules on a wagering requirement before multiplying by volume: the volume only matters while the requirement is running.