1 million cap APR/BPR and trust 10 year charges

Just looking at the HMRC guidance for allocating the 1 million APR/BPR allce to trusts in chronological order, If a settlor settles 300K of qualifying assets into trust 1, £300K into trust 2 and £300K into trust 3 does that mean each trust would only have 300K allce and 100K is unused unless the settlor creates another trust i.e. the existing trusts cant benefit from the full 1 million?