Or are you saying that if I went to an ISP with the reduced IP address, they could disclose details of the person, if they only had 1 account within the range of IP addresses that the restricted IP address covered? This doesn't seem particularly likely to me? I thought ISPs hold a block of IPs and dole them out on that basis, and so resulting in only a loose connection between IP address and location?
On large companies, that would be out of scope, because whilst the reduced ISP may be linked to 1 large company, the assumption would be that the large company had multiple employees. On that basis although the account may be linked to a particular employee, no one employee could be singled out because multiple people would be relying on the same base IP potentially I would have thought?