Daily or Hourly or IP or Other Data Limits or Throttling?

Well Ive been able to ascertain that there is a monthly data limit for my account.  Luckily we never even get near it.

But last week i was preparing for a business trip.  Part of this preparation is downloading a number of films to an ipad from Itunes.

Why?  Well the wifi service at hotels is horrible usually.  It's easier to just download a bunch a of movies ahead of time and then not worry about the atrocious connection in the hotel.

So I start downloading videos from Itunes and at first it is BLAZINGLY fast.  No one else was even awake in my house.  No PCs were running.  Nothing else was streaming.  So I was getting the 150mbps directly to my wireless device (yes i have 802.11ac in the house).

Then, like a switch had been thrown, my connection speed drops dramatically.  My previous speed disappears and suddenly it takes all night to download even a 30 minute episode, that previously had taken just a few minutes.  After the entire night had passed, i had only downloaded 58GB or so.

So is there some kind daily limit for downloads from Cox?

Is there a limit for itunes from Cox?

Is there an hourly limit from Cox?

Is there some other kind of limit?

I'm not angry about this.  I'm attempting to determine the source of the issue because it could be:

1)  My modem

2)  My router

3)  My ipad

4)  Itunes

5)  My neighborhood's Cox equipment

6)  My home's wiring

7)  Or even Cox policies

If it is some kind of Cox policy i can simply download videos for several days ahead of my next trip, instead of getting it all in one evening.

If it isn't Cox, then I might have some troubleshooting to do on my own equipment.

Thanks for the help!