Reading various threads and youtube vids, it seems if a battery is below 90 percent useful life, it runs a much increased chance of failure, regardless of what the lamps or asst software indicates.
Batteries can fail at any time no matter what percentage. What will happen as batteries age your flight time will decrease. I have two batteries which are 20 months old with 87 & 85% battery life but only fly for 6 to 7 minutes and both are just under 50 charges.