Its worth looking at the Fire aviation site for costs of delivery on the various types. The appropriate page is dated 13/2/20.
The Dash is not listed because the only operating examples are French registered and the FA figures are based on the US contact.
The French Dash 8s are also use for general civil defense work as both freighters and pax and as such can justify newer aircraft compared to limited use fire bombers.
Wunwing