##### Validity Time Computation Details

**If you select N symbols the remaining subscription time will be reduced by a factor of Log(2N)/Log(2). As shown in the top row of the Key Value table at right, this means that if you have 30 days remaining for 1 currency pair, you will have 15 for 2, 10 for 4, 7.5 for 8 and 6 for 16. (If you later remove some symbols so you only have M (<N) pairs then the remaining subscription time will be correspondingly increased).
If you change the frequency from 1 sec to a higher interval T the remaining subscription time will increase on a logarithmic scale proportional to
Log(60T)/Log(60) where T is in seconds. As shown in each column of the Key Value table at right, this means that your remaining validity time is doubled as you move from a frequency of 1 second to 1 minute with a fixed number of symbols. (If you thereafter modify the setting so the interval T is reduced the validity time will decrease in the correct logarithmic proportion).
Validity time computations are done accurately by the management system after each configuration change or license key installation. This is done by always re-applying license keys in order of their expiry date and by keeping a record of a remaining virtual validity time credit of each license key added (even if the actual remaining validity time of a license key is truncated by its expiry date). The management system dialogue is transparent and asks user to accept the new validity time before proceeding with the configuration change request.**