Does using Lan device access via M2web use vpn data?

I made my viewon application and a siemens HMI available via the “add lan device” option on ecatcher. My question is when my customers view the HMI and viewon application via m2web does it go against the account vpn usage?

Yes, It does. Any data going through the VPN connection will count again the VPN usuage. This will include eCatcher and M2Web.