Ah... I checked again and yes need it.
https://github.com/openhive-network/hive/blob/4913627cf74cf0dd9d65476ab101042ba5a4239d/doc/devs/operations/39_claim_reward_balance.md?plain=1
You need "A" amount and because the minimum is 0.001. That's how much you need to claim. Although there is another way that peakd now uses to also add an amount.
And you can also add by removing and then canceling ... which effectively adds back what was about to be removed.