A small nuance of the provider's network architecture

Question

Computer networks

Faced with not absolutely unambiguous situation. One of Peter's providers. IP addresses are issued to clients via DHCP. Of course, the "gray" IP behind the provider's nat. Binding to MAC address. The client lived for a long time with a cable directly plugged into the computer and did not know grief: the Internet worked. But there was a need to distribute the Internet via WiFi to other home devices. An elementary TL-WR543G router was pulled out of the trunk and connected. MAC cloned, IP obtained, no internet on computers. We look at the status of the router: ./23 mask (255.255.254.0) and IP like xxx0. Zero in the last octet. With such a mask, there is nothing criminal, it should work. But the router on the status page shows a bunch of RX and 0 TX.
Call to TP:
- Hello! Here I have "... such a situation ...", can I change the IP issued to this client?
- We are fine. Your router is at fault. You can change the IP in your personal account. It costs 50 rubles.
We talked for a long time, but that's the gist of it.
I paid, changed - everything works. But I had 3 questions:
1. Is this a mistake in the network architecture? From the point of view of the formal rules of the IP protocol, there are no violations. But to issue to the client "0"? It is clear that sooner or later the above-described case will arise.
2. Is it ethical to take money to change a gray IP? A penny of course, but the fact itself. Out of the air. And okay, if you change it just like that (I wanted to). But the client came up with a problem. Well just change it. 3 mouse clicks and the client is satisfied. The categorical answer is "no". Even after the operator "consulted with the senior engineer" for several minutes.
3. Yes, the problem arose in conjunction with a specific router model and network architecture. And the probability of this zero falling on an incompatible router is negligible. But after all it would be possible to go towards the client. And keep this in mind for the future. Change a few lines in the configs and ban such IP - 30 minutes maximum. Or don't care?

Answer 1

1) Is not. On one tsiska with a certain firmware, I did not respond to addresses ending in 255, at the same time real traffic went. Under all devices you will not adapt. if there are sneakers sold in pairs, and you do not have one leg, is this not an architectural error?
2) Unethical. But if they have a service like "change gray address", then this problem periodically happens to others
3) It is not known whether to change a few lines in the config or give a couple of bucks for introducing new functionality into the billing system. Or maybe your poppy is tied to a specific IP address, and in order to change this, you also need to change our agreement with you?

Answer 2

3. in this case, the contract does not need to be changed. press the button in your personal account and agree to the withdrawal of 50 rubles. from the account.