Federation Commander

The cutter is an actual ship, even if only a civilian ship pressed into auxiliary service. As such, it operates as one.

The skiff (security or otherwise) is a gunboat precursor. It isn't a "full ship". In size, it is actually close to a shuttle than a full ship. As such, its capabilities are going to be less and the skiffs capably show that quite clearly.

So,it's somewhere between an interceptor and a cutter in size then. That explains the shields,but it's still very costly for what you get Mike.