You do need to get a clearer understanding of what you will be getting for the price. In order to ensure coordination between, for example, a branch panel's feeder breaker (on the distribution panel upstream) and a branch circuit breaker, all you need to know is the choice of breaker models and their settings. You overlay the two curves, and you can verify coordination. That is not a complicated or expensive process. The manufacturer will have done it many times before, and they already know what breaker types they will be using.
Different from this would be a short circuit or arc flash study. Those require you to provide much more information (i.e., into the computer model). This includes every feeder size and length, every transformer's ratings, every panel's short circuit rating, and every breaker setting. This makes for a more complex, and more expensive, calculation process.
So if you need to be able to prove that every one of the 35 panels has a short circuit rating that is higher than the amount of short circuit current available at its location, you won't get that with just a coordination study. And if you need to provide arc flash labels, you won't get that with a coordination study either.
So once again, I would suggest reviewing the manufacturer's proposed work scope, and make sure you are getting everything that you need for the price.