understanding fortinet summary report

Hi, we are having little confusion on Fortinet daily summary report

we are using FG60D our daily internet usage report not matching with the data provided by my ISP.

My question is Device usage and VPN usage are separately listed in the summary (refer the image) like 14.3GB +8.4 GB = 22.7 GB overall usage

or Device usage included with VPN usage means 14.3 GB is the overall

Sorry if I am not clear

Thanks, Nihal