The countdown is weird indeed - it counts down to the end-time of the offer. Not the start time.

So the discount percentages differ for economy fares, and for business its a static 20%. The 70% is from mid Jan to mid March. Let's see, there are a few flights that I am considering. One is quite expensive (180 euro in L-class) but that falls within the 70% timeframe. Tricky point is if you'd ever need to change such flight, the price will then probably revert back to the original level (180 in this case, which I consider too much for a one-way flight off-peak in March).