giving more hash power is less expensive than giving people refunds... especially if they have to refund in btc (which i can't see how they can afford to do, even if they promised it)
You've miscalculated something, I think it is just the opposite. The refunds are the cheapest option for HF for two reasons: If they refund the BJ they can resell that miner again, and also they don't have to give the MPP to the buyer and can also resell that MPP. Refund once, sell five times. Especially if they can refund BTC partially, not the full BTC amount which they obviously plan to do. I do believe they will not ship on purpose to provoke the refunds and then sell the "miners-in-hand" which will sell like pop-corns.
If only HF planned quite that well! As if they did, they would have delivered ages ago... Frankly I don't think they are close to being that organized or financially savvy or they wouldn't be in the situation they are in now!