The purpose of this strategy is to trick Google into thinking the sites are owned by different people to give higher value to the links. It's based on a patent that was published half a decade ago (meaning it was written years before that), and isn't something anyone really does anymore.
Google is an ICANN-accredited domain registrar and has full access to the WHOIS database.
Google knows who's the registrant of every domain, and what name servers the domain is using. Google knows your sites have the same owner even if they're on different IPs.
You're wasting your time, and you're not going to get anyone to allocate you hundreds of IP addresses anyway, let alone in hundreds of different ranges. There are not going to be any IP addresses left within 12-18 months, ARIN/RIPE/APNIC don't give out IPs without proper justification, and SEO is not a proper justification.
So much of the web hosts with the same large hosting companies anyway that two sites being within the same class C range of IP addresses does not mean they are owned by the same person.