from a s6 to my laptop

laptop only gets a tether connection if my phone is connected to another wifi


so is it using the wife that my phone is connected to
or is it using my phone internet

Not sure if your phone can be used as a router. Dont think so but its possible.
If that is the case then yes youre using the wifi through your phone that is serving as a router.

Don't know

Best way to know that is when it is connected and working, turn off your mobile data and see what happens.

You need to install the latest samsung kies