I set a reminder on my smart phone for the 60-day point, when discounts open up, and the 45-day point, when instant upgrades are available for VIPG, then go and check the availability. If there is availability and it's at the 60-day point or later, there are discounts available for any VIP. Instant upgrades work similarly at the 45-day point for me - timing is different for different VIP levels, of course. In my experience, the automatic upgrades at that point are the ones that are iffy - instant upgrades depend only on the availability at the base level you reserve and the upgrade level that you want - upgrade path dependent, of course.
My best guess is that for the third reservation you were not within 60 days of the check in date yet. Either that or you saw that there wasn't availability and didn't cancel the original reservation, which is wise.