I've always used HP inks, but then my employer was paying for them... Can you just add a bit to your costs to offset increasing ink costs? Or turn down the saturation just a bit so you can save on ink?
I ran a Canon Colorado 1650 for a while, and we had to buy two cartridges at a time for one color and they always expired before we could use the 2nd one... On top of that, the machine wouldn't let you use expired ink. As far as I could tell, that was such a money-grab that HP's processes seem pretty reasonable to me.