Just a quick follow up:
I still don't need to sign in multiple times so I'm still good.
In the other thread I just responded to (same issue, see link somewhere above) I did make a song purchase from iTunes using credit from a previously redeemed gift card. Other than that, nothing on my end changed and I only have to sign in when making a purchase.
Have any of you made a purchase while experiencing this problem?
I am still of a mind to think that there may be some "certificate" issue with the Apple servers where, in a perfect world, the first server accessed would authenticate my access and any other servers would accept the certificate from the first server. In the problematic world each server accessed required separate authentication.
I'll take some screen shots of my preferences and add them soon. Perhaps that info may help?