When you use your iPad's WiFi and connect using an Exede (now Viasat) connection it uses your Exede (Viasat) plan's data.
Assuming you have a cellular capable iPad, it will use your cellular data when using a cellular connection.
Don't fall for the typical Apple mis-statement that says to save data use your WiFi connection - what they really mean to say is to save cellular data use your WiFi's data... and you'll be using data.
As others have said, an iPad using Wifi at home, is using Viasat data. to stop that, turn Wifi OFF on the iPad so that it has to use ONLY cellular data.
Cellular data is that provide by whomever you pay for iPad service (Spirint, AT&T, Verizon, etc...) Wifi is data provided by an ISP like Viasat, Caomcasr, Xfinity, etc... via a wifi or wireless router.
