Why am I getting an SMS and push notification requesting that I wait for 18 hours, whereas for some other users it is 12 hours?

For all ATM activations done between 6.00 p.m. and 12 a.m., an 18-hour activation period is required, whereas for those who perform them between 12.01 a.m. and 5.59 p.m., a 12-hour activation period will be required instead.