Unit Constructions Times

[Fatboy]

I have noticed that actual unit construction times can be much greater that those show in construction mode. Does anyone know the factors that cause unit construction days to 'blow out'?

[General01]

There is a certain degree of randomness to how long units take to build: At a guess, i'd say +-10%, for all units. Additionally, if a constructing stack is under siege or out of supplies, it takes about four times longer to finish.