okay I contacted IPS support directly to get this figured out. Apparently I can set it up so those rank benefits work, the way you said - Make it so its 0 day grace, and 1 day renewal. The only problem is, even with that "The customer cant make renewals" button clicked off, it makes it so at the end of the product's time, the user can manually click renew to renew the product which is not what I want- I want it so they are forced to buy a new product, as they need to be sent a brand new key.
My problem of it making it longer than 1 day even with 0 day renewal is I set the price to $0 for testing purposes. Once I set it to $10, and made it a manual payment for testing, it worked. Showed product expiry of 1 day.
According to IPS this must be done via 3rd party software, so I need to look for a dev.