I made sense if you think about paying for updates in terms of paying for their work. If you wait 3 months and then get 12 months license for updates you effectively got 15 months for a price of 12. They may be hesitant to offer that to you on a discounted price. I think it makes perfect sense.
The 3 months were spent using the previous version, so you didn't get the benefit of the improvements in the upgrade. But this scheme means you paid for them anyway.
Anniversary date: March 1st
Upgrade announced: June 1st
You get around to purchasing the upgrade: September 1st
You get to use the new version for 5 more months (until March 1st) before your upgrade premium expires.
You didn't "use" the new things but you get them now. They've spent 3 months developing stuff which you now want basically for free. Think about it as paying for work, it takes time to develop features, say 1 feature a week. You didn't pay for 3 months, they added 12 things. You now get them without paying if you were to get 12 months since renewal.
It really is no wonder they don't want to offer that on a discount.
