Meraki devices; there is no support for the sysUpTime SNMP object used to calculate rate of counter advance in monitoring applications.
Meraki support line has confirmed that this is the case. At this time, there is no alternate objects available for doing this calculation and Meraki doesn’t have a recommended method for generating counter rates using available SNMP information for their products.
Using the Meraki cloud management interface, you can see a display of the data on the interface in Kb/sec. This is a method to get that data.
The bottom line is that the device does not provide information sufficient to calculate rate information for any interface counter so no workaround is available.