Nighhawk M1 data offloading

I now have two internet connections at home. My ADSL which runs at 4 GBPS and drops out and my nighthawk which is over 20 GBPS, however the nighthawk has very very limited data. I noticed the data offloading on the app I dowloaded. My question is, can I download some of my used data to my ADSL and basically pay the normal ADSL rate for it by continually offloading my used data? my usage is around 500 G per month and the nighthawk max is 80 G.