@Michael-Navarro I would guess the difference is just the license.

The 365 license will grant you access to Sound Forge Audio Studio 16 and the newer versions 17, 18, 19 etc. after they are released as long as your 365 license is valid.

The perpetual license will only grant you access to version 16 but not for newer versions. But you don't need to renew the license each month or year like the 365 license.