How much details are enough to get justification for RIPE allocation?

Hi

I've been working with a company who is network-wise splitting itself off from its parent company and thus requested a business internet line with fixed IPs (technical and org-level reasons). Currently we have a /27 from the parent and make use of roughly ~17 public IPv4 addresses when I count DMZ and office NAT gateways together - hence why a /28 is already on the low side for us. If we were forced to we could likely squeeze more thing behind a IPv4 to IPv6 reverse proxy but some services won't be so easy.

On the cost side the difference between a /28 vs. /27 is not that high, thus our boss went safe and requested a /27. But now we got a form from the future ISP requesting pretty detailed information about our current actual use of IP addresses like

• number of hosts with function, vendor, OS (the vendor surprised me a bit, most is virtualized)
• network schema if you request more than a /28
• Questions like whether we are returning currently-used IP space, and if not, why (no: since it's owned by the parent and will be reused internally there).

Anyone in the european space who could share similar experiences? Is there a tendency to only grant you the requested IPv4 subnet if you provide very exact data on the network? Is there a tendency to force you i.e. into a /28 instead of a /27 if you can currently justify let's say 18 IPs but not 25?

I should mention that the future ISP in question is one of the incumbents in the national market here and has definitely plenty of IPv4 address space available. Is this a normal procedure? To be honest I've only worked with ISPs where the company had maybe a /28 at most so this is the first time I've encountered such a form.

Looking forward to hear about some experiences. Oh and yes: One reason of getting independent is the question on IPv6 being unanswered by the current upstream for years.