It seems like that's more of a thing to combine multiple dispatcher sets using potentially different algos? That could be useful in some other scenarios, but in the current setup this is working perfectly with the applied patch.
My point here is that algo 13 seems to be broken (failover does not work) if the first selected (highest priority) destination is marked as inactive. The xavp var is not set.
While it's being probed but not yet inactive, the call distribution will time out - but the xavp will be set and the on failure logic can trigger as expected.