That isn’t unusual. Many kids have areas of strength that come relatively easy to them and areas where they need to work harder. No surprise.
Some kids will excel with only a modicum of effort, some will excel with huge effort, some will have to work very hard for Bs. These schools are attracting the top 20% of higher from other schools. The competition is tougher now. Some students will be mediocre in the new context. That’s just a fact. Im always surprised when that surprises people. These schools are known for rigor.
And back to the topic of the thread, if you choose a school with seated meals, you adapt and engage and learn to deal with it.