To answer this question- the surrenders are to give you the lowest price possible on your Anthology XII upgrade. An upgrade from UltraChannel + AXI is a bigger discount than an upgrade from AXI alone.
However, if, as in your example, you have 10 ultrachannel licenses, it is only counted once and you only have to surrender 1 license. There are edge cases in which a user might need a standalone license in addition to the bundle license, usually in the case of needing more activations than are allowed in a single license. In that case support would happily assist you in depositing an nfr license to cover the extra activations required.