Yup, they are probably holding out on Groestl from the X10, so they can get sales for the BK-G28. Once they get enough sales, then they MAYBE release Groestl for the X10 later on. Remember, when they release NIST5 for the X10, it was probably the most profitable for like just like a day or 2, because everyone switch to it. Then it wasn't profitable as other algos anymore. This will be the same fate as Groestl.

Also remember, when first buying X10 when it was released, BTC was near all time high last year around November/December, so don't be expecting high profit returns this time around.

Lastly BK-G28 has all the same algos as X10, so all the algos will be saturated in increased hashrate and difficulties and profits lower for everyone not matter what.

This won't be a smart buy at this time of the market because the efficiency isn't that big of a jump compared to the X10 from Giant+, but then again, there will always be people buying ASIC no matter what anyone says.