I have been advised that I should transfer part of a balance of one credit card to another card in order to maintain 50% debt to credit limit ratio on _each_ card even though my _total_ debt to credit limit ratio is already below 50%. (Most of the debt is on one card for convenience.)

I could easily transfer part of the balance to an unused card with the same interest rate. Obviously, doing so would not effect my total debt to credit-limit ratio; rather, it would be a kind of shell game. Logically it should not matter to credit bureaus if I carry a debt on one or two cards. In fact, logically, I would assume that moving debt around from one card to another would hurt my FICO score. However, financial issues aren't always "logical."

Bottom line:
Is one's FICO score effected by one's _total_ debt to _total_ credit-limit ratio?
Or is the FICO score effected by the debt to credit-limit ratio on _each_ credit card?

Thanks for your help.

It is OK if you put all the balances on the card with lower interest an keep the cards with no balance open, It will not change your debt/credit ratio or your score, really is showing to the rest of the credit card companys that you know how to manage your finances, they will probably offer you a better deal.
In the other hand 50% is not the best for your score if you take the ratio down to 25 or 15% you will see an increase of at least 10 to 30 points on your credit score.