no regular shields would be able to redistribute power to a failing shield grid automatically. that's a basic redundancy routine that would be common in shield technology. OBVIOUSLY you transferr power to a more needed area.
REGENERATIVE....this suggest something is being regenerated or recharged. Regenerative shields suggests that the shield grid either has a backup power supply that regenerates the shield generators/grid, or it uses incoming weapons energies to regenerate the shields grid and generators. the latter seems more practical and likely in battle.
In between fire or battles shields should automatically recharge using repair techniques. A generator when not under duress can fufill it's shield chargine capabilites. but to suggest regeneration means that the shield technologies not only fufill their obligations under duress but do the job of recharging also under duress, a situation that normal or standard shield generators and grids cannot do. this isn't to say regeneration technology isn't within limits, eventually it is fed so much energy that it's transistors and energy translation intermixes can't keep up and then degredation happens.
it would reasonably be the way it works.
logically this is what regenerative sheilds are.