Thanks. As I noted in my previous post, I have successfully imported Amex transactions from this same account, as recently as two months ago, so the process is familiar.

The last time I used it, my Amex account was correctly listed as one of the bank account options. Now, it isn't. If I create a new bank account - and thus, a new account in the Chart of Accounts - then I will have two disconnected/unrelated Amex accounts, which is not useful. 

The link to the article is appreciated, but doesn't appear to contain any information that pertains to my problem.

Batch entry, or individual transaction entry, appear to be my only choices. That's unfortunate.