I'm running tests on the Bandwidth Manager to limit quota, and I noticed some devices are able to exceed the maximum before being blocked. Is this due to a delay in the program refreshing to check for usage? One was blocked at 102MB while another made it to 120MB.
Yes, there is a short delay. All usage is summed at 30-second intervals and then quotas are enforced. Therefore, occasionally users can exceed their quota by as much as they manage to download in the maximum time frame of 30 seconds.
Usually it is not a problem as typical usage is scattered throughout the day rather than being one continuous download. If however you have such a case and/or have very scarce or expensive data traffic allowance, you can simply decrease the quota a bit further.