Even then, taking that fluctuation and where costs are now, I struggle to see it going crazy, or over the 300m as some fear.
The way I see it, 65-70m for the hotel. 35-40m for the commercial block. Those two, the size and layout they are, even with the sails, is not that unreasonable. The stand is more complex and much harder to guess, say 60-65m for circa 15.5k m2, with a bit more for unknowns. Then there is the immediate city square partially open areas etc, to a 200m build cost. Then the fees, contingencies and infrastructure etc for the rest of the investment.
All obviously just my own opinion and how I see it at a very loose level. Appreciate people have different takes and experiences. Will watch with interest either way.