Attack Simulator - Randomize Send Times

Hi,

I've read this article: https://techcommunity.microsoft.com/t5/security-compliance-and-identity/announcing-exciting-updates-to-attack-simulation-training/ba-p/2455961

I'm now preparing one simulation, and there's still one question which is not clear for me.
I want to randomize the sending times, to avoid the "crowd" effect of everyone receiving at the same time. But if I define the start date as 1 of October for example and end date for 15 of October, how will the randomization of email sending happen?
Usually I leave the campaigns on a 15 days timeframe, to give enough time to any user which is on vacation for a week for example. But if the randomization occurs between the start date and end date, that may mean that some users will receive the email near the last days?

Thanks