[GS] Harvesting woods with magnus, colonization and ancestral hall

[10101100]

I'm trying to understand the situation: I have magnus, colonization and ancestral hall in the same city. The worker is on a woods tile that gives +70 prod when harvested. I start building a settler, 0/200 prod, I harvest the woods and now the screen says 140/200 prod

That's only 100% increased production, I assume the three are additive and should stack to give me +150% harvest value from woods. What's going on?



EDIT: I'm a dumbass, the base harvest value of 70 is already increased by magnus