Quote from comintel:
It should take effect a day later now that you have checked the box.
I put in a support ticket yesterday just in case and was pleasantly surprised that it was taken care of before close of business. They basically did a reset of the permissions to ensure everything clicked.
I take it from your post that changes typically take a day to become effective. I shall bear that in mind.
It works fine now, and I can run just the paper trading account with no hitches.
Thanks to you and everyone else who chipped in.