// This:
		uint old_rate = t->growth_rate;
		if (p2 == TOWN_GROW_RATE_NORMAL)
			t->growth_rate = GetNormalGrowthRate(t);
		else
 			t->growth_rate = p2 | TOWN_GROW_RATE_CUSTOM;

// Should be:
		uint old_rate = t->growth_rate;
		if (p2 == TOWN_GROW_RATE_NORMAL) {
			t->growth_rate = GetNormalGrowthRate(t);
		} else {
 			t->growth_rate = p2 | TOWN_GROW_RATE_CUSTOM;
 		}