Ok to make it easier for you.
If they had updated in March
I would have had my iPad a year. my old iPad would sell for around £469, and it would cost me around £100 to upgrade.
Now I either have to pay £100 to upgrade after just 6-7 months, OR I wait till the next upgrade by which pont my iPad will be worth about £100-£200 less then it would have been worth if they had not just upgraded it. So it will then cost me £200-£300 to upgrade instead of the USUAL £100.
Meaning I would be out an 'extra' £100-£200 in the 'SAME' time period I usually am only out £100. Hence I am down money about £100-£200 to be exact.
You're not down anything. No one is making you upgrade. That's your choice. You made an investment, you may get less cash back then you originally expected but you're still getting a better resale value then any other Manufactures products on the market.
You have to pay a little bit more to upgrade to the latest and greatest? First world problems much?