As per the doc ...
QoS Interval (Multiple of 'Interval'): specifies the monitoring interval between each sample collection for QoS information. For example, If the interval is set to 5 minutes and number of samples is set to 5, the average CPU utilization for the last 25 minutes is displayed in the QoS message.
Note: If “the value is greater than 1, the probe only calculates the average data for CPU monitoring. For disk, memory, and paging QoS messages, the probe generates the QoS messages with the current value. The probe only uses the QoS Interval to reduce the frequency of QoS messages.
So, the number selected in "QoS Interval (Multiple of 'Interval')" is multiplied by the "Interval" to determine how often the QoS is sent.If the interval is set to 5 min and QoS interval is 1, then the QoS will be sent every 5 minutes.