Hi WB, and Happy New Year to you too!
IMO, GEMb has different departments handling different creditors.
I have a J.C.Penny card that I just love! In a little over a year, I've gone from a $300 cl to $1,500 today.
On the other hand I have a QVC card that I've had for only 2 months with $500 cl on it.
I had a Sam's credit card with them several years ago...made the horrible mistake of paying at a Sam's store.....the accounting dept, lost my payment which caused GEMb to not only close my account but also charged me $16.00 late fee AFTER I pif'd them....
This in turn led to that measley $16.00 being charged off, and it went on my cr. It was a fatal baddie until I talked to the debt recovery dept. there and they completely deleted the charge off from all my cr's.
Moral to the story...NEVER pay your cc bill at a store, and allow PLEANTY of time for them to receive your payment.
As far as your applying for different cards with them...the results 'could be' the same, depending on your FICO scores. I know that's not much help but the best I can offer.