The restaurant is either subsidising the rooms or the other way round

Rooms and food have completely different cost structures, and in an independent hotel they are frequently reported as one operation because they share a kitchen, a store and a set of staff.

Three consumers, one store

Room service, the restaurant and staff meals draw from the same purchases. Without attribution, food cost is a single percentage that describes none of them accurately, and staff meals in particular are invisible.

Recipe costing where it pays

Not for every dish. For the fifteen that account for most covers, which is usually where the pricing decisions matter and where a supplier price rise does real damage before anyone notices.

Wastage is a decision input

Recorded wastage looks like an admission of failure, which is why it goes unrecorded. Unrecorded, it becomes part of food cost and stays permanently. Recorded, it usually points at two or three dishes with unpredictable demand, and that is a menu decision rather than a discipline problem.