I imported my list from SOC to Zen. However, I could never get used to the Zen system so I haven't used it. Plus, the way they list the reminders isn't the greatest. They list it in alphabetical order and not by date. To me, it would make sense to list them by upcoming birthdays so as to not miss one. Maybe there is a way to change it, but if there is I haven't figured it out. And the support isn't that great from what I remember.
maybe I need to call them and figure out how to make the DOB transfer over.
I think the issue you are having I wouldn’t have. I make sure that on the 25th of every month I have all my birthday cards sent for the following month. But send out cards will have it to where it arrives a couple of days before their birthday and I’m assuming Zen does as well