Giving more mahr to the second wife

Q: In Islam, a man is allowed to get married to 4 women. If he wants to marry a girl when he already has his first wife, does he have to mention the same amount of mehar that he had given to his first wife or can he give his second wife more than what he gave the first wife as mehar.

If he wants to give his second wife more mehar than the first wife's mehar, is there any problem in that or should he maintain an equal amount of money for both?

Taking out insurance to get RMI accreditation

Q: I have a tyre repair shop. I want to get this RMI Accreditation for it. Its like a motoring board and carries weight in the vehicle repair and service industry.

One of the requirements in order to be accredited is that I must have a 3rd party insurance to the value of 500k. So if something happens to the customer's vehicle in the shop or a customer's vehicle gets stolen or damaged, etc. the insurance will cover the vehicle.

So the insurance won’t be for my business, it will only be 3rd party to cover the customers vehicles, etc.

Is it permissible to take out that insurance to get the accreditation or must I stay away from it completely.