If, as you say, not one of the tiles are loose or chipped but the finish has worn off, I would probably go over it.
I would have to make sure that they where clean and dry with no wax on them.
You would probably have a bigger problem trying to remove the old asbestos tile than it is worth.
It sounds to me that the person who installed the old tile knew what he/she was doing!
Only my opionion, I'm sure you will get more!
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