It's also TRUNC() not FLOOR() (not that it probably matters). For example, pop growth:

Min(BioFactor*Trunc(Round((MaxPop-CurrentPop),0)/3,0),BioFactor*Max(40,Round(0.03*(1-Taxrate)*CurrentPop),0))

and loss:

Min(Round(BioFactor*(0.05+0.15*Taxrate)*CurrentPop,0),Trunc(BioFactor*Round((CurrentPop-MaxPop),0)/3,0))