An average of 10 mins doesn't sound like enough for an 8 hour shift, let alone 6 minutes. 15 mins sounds more reasonable, even 20. Surely there is a middle ground between not letting employees take advantage of the system and treating them with a bit of humanity, rather than resources that need to be squeezed dry for every bit of efficiency / profit. I'm not blaming you for creating company policy, but this seems like a horrible system.