I'd bet this could be improved upon.  Unlike BTC wallet, KHC does not generate 'dummy work' when there is none so that is a big bonus for solo miners but while pointing at the pool I have yet to see my miner go idle when there is no work available, aside from that KHC is quite new being a 320bit hash so the miner kernel could potentially be optimized quite a bit more than it is.  Took a while before a DRK (x11) optimized kernel was released with sgminer, and it was improved upon further recently.