Yeah, calculation in bitAssets are really, really tough at the moment!
Seems I am not alone. on BlockTrades it says, To receive 600 BitUSD, deposit 376.20519551 BTC and you can't buy bitUSD at all with BTC.
BlockTrades works off the actual markets, in this case the BitShares DEX market (and to a limited extent off feeds for some markets). Right now, it looks like we're quoting 173BitUSD for 1 BTC. This is certainly buyable, it just means the market is valuing BitUSD higher than USD (this isn't that uncommon).
That valuation makes sense. I was referring to this below. Maybe I need to login or just a display bug?
No, looks like there was a problem where the database for our live site was missing the market pairing for the bitusd->bts market direction, so it was unable to provide pricing in that direction. I've added it now, and it's providing proper pricing for that direction.
Not sure why it was reporting such a strange value for receiving 600 BitUSD for Bitcoin, but after updating the site to our latest code, it's reporting 4.252 BTC for 600 BitUSD, which I think is an accurate reflection of the market.