Authorize dot net ARB "creation date" start date"

Please forgive my ignorance, I am not totally clear how this all works, but I will explain my concern:

I have a website with recurring billing, when I submitted my charge to Authorize.Net for a (7) day subscription starting today, my credit card got authorized tonight, and in authorize.net is said "authorization w/auto capture" however, the "creation date" and "start date" are not the same.

My creation date is today 4/16/15 and my start date is exactly (7) days from now, 4/23/15, exactly the duration of the first week of the subscription, coincidence ?

I THINK my programmer used AIM as first payment then the ARB gets info from plug- in on site (I have just turned on ARB on authoize.net, but have not needed to configure it with dates of auto rebilling, etc)

My question is...should "creation date" and "start date" be the same ? I am thinking yes they should since my credit card is being authorized with auto capture today, why would the subscription need to start on 4/23/15 ?

Thank you so much for your help!!