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- VALUE_1 - maximum number of units inside subscription bundle,
- VALUE_2 - total number of units used, i.e. the sum of units used by the subscription bundle itself and by other subscription bundles (when the bundle is used as a surplus bundle),
- VALUE_3 - maximum number of units that can be rolled over (the maximum number of units that can be used as surplus by other subscription bundles). As this value indicates a part of value_1, it will not make sense to have a number greater than value_1.
- VALUE_4 - total number of units used by other subscription bundlesrollover. Value cannot exceed value_3. Note that value_4 is not a simple value, it is used as "a value from which other information can be calculated" (for more information, see below).
Value_4 Explained
The difference between value_3 and value_4 (i.e. value_3 - value_4) is supposed to indicate how many units are available for rollover.
This means that every time units are used (i.e. some value is added to value_2), also value_4 is likewise increased with the same number of units, as this now indicates that less units are available for rollover.
The rules for how/when to update value_4 are:
- When the bundle is used as a surplus bundle by another bundle, then value_4 is updated with the amount of units used by that other bundle.
- Note that the process that updates value_4 shall make sure to also update value_2 with the same amount of units.
- When value_2 is updated it needs to be checked if the total units available in the bundle is now less than the number of units that can be used as surplus. If this is the case, then value_4 needs to be updated such that this is no longer the case.
- In more mathematical terms, if (value_1-value_2)<(value_3-value_4), then adjust value_4 such that the '<' becomes '='. This means that value_4 shall be set equal to value_3-(value_1-value_2).
Examples
Suppose a bundle has value_1 = 500, value_3 = 200. This means the bundle has 500 units for charges in actual period, from which 200 units may be used by charged from other periods.
Suppose now that 190 units have been used in a period, i.e. value_2 = 190 and value_4 = 190.
- If some usage with 25 units is processed by the bundle within the actual period, all 25 units will be added to value_2 (as all units belong to the actual period), but value_4 will only be added 10 units as there is a limit of 200 units. Consequently, value_2 = 215 and value_4 = 200.
- Instead, if some usage with 25 units is processed by the bundle outside the actual period (i.e. rollover), only 10 units will be added to both value_2 and value_4. Consequently, value_2 = 200 and value_4 = 200. This means that the period still allows 300 units to be used inside the period, but no units are left for rollover.
Subscription Bundle Update Manager
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