J. L. Brown
Emperor Mongoose
Geir is using the price for the Tigress from HG Update 2022, p284. Because his starting price is lower than yours, the final time-to-completion is shorter. Other than that, it looks like the results align quite nicely.
I would also love to point out that the Tigress spends 90.25 GCr on just the Hull; and similar amounts on both the M-Drive, J-Drive, and about half of that on Power Plant. Something like ~89% of the entire cost of the ship is in just those four separate components.