The number of client from getNetworkClients() is not the same as getNetworkClientsApplicationUsage()

[Rohnny]

I'm trying to get a list of client on each network with total traffic usage and a list of applications each client used.

I used getNetworkClients() to get list of clients on the network and getNetworkClientsApplicationUsage() to get specific usage of each client.

But the number of the client on the first and second result is different. 

The output from the getNetworkClients() has more clients that is now shown on the specific usage (And this missing clients are only from one particular network!)

Also the sum of traffic usage is also not the same. Usually the usage of each client from the getNetworkClients() are greater than the data I get through getNetworkClientsApplicationUsage() 

Here is some part  of my code:

networks = dashboard.organizations.getOrganizationNetworks(org_id)

clients = dashboard.networks.getNetworkClients(net['id']
                                               , timespan=60 * 60 * 24 * 7
                                               , perPage=1000
                                               , total_pages='all')

client_traffics = dashboard.networks.getNetworkClientsApplicationUsage(net['id'], testString,
                                                                       timespan=60 * 60 * 24 * 7,
                                                                       perPage=1000, total_pages='all')

Other part of codes are just put all the data into csv format.

P.S) I read the post that the usage difference could happen because of the cached value. Could this be a reason of my case too?