I think @roland is trying to say that just because it has worked doesn't mean it will continue to work because the ACME spec doesn't guarantee it. It also doesn't mean it will work with other ACME providers. The best defensive coding stance for a client is to always check the status of all authorizations in a new order.
99 extra requests in your example is only seconds of additional delay. If all of the previous authorizations are still valid, there's no additional server round trips beyond that first check. And the ACME server is already expecting the traffic because that's how the spec is supposed to work.