Maxxis DTH below minimum psi?

I have a Maxxis DTH 406 20 x 1.75. I know it's a BMX tire but I have it in my folding bike.

I usually run these at 90 psi. but always wondering if I can lower it around 60 – 70 psi.

note on the side wall, tire is 85 – 100 psi

thanks for anyone who could help 🙂