I agree with Fluphen, this mechanic seems to some degree counterproductive and not well thought-through. I myself mostly use the early placement strategy, because delaying Iron feels incredibly bad. it hurts not only your military, your expansion, but also your sheer production and eurekahs/inspos. still, I am very thankful for the write up since I had no idea what was actually going on. regardless, I don't think I will be using the discount strategically very often.