I suspect this is one of those conditions added by the legal weasels to avoid litigation by disappointed customers. I've been printing with an Epson 7600 for several years, and some of the ink "cartridges" (boxes really) have been installed for over a year at the less used positions (cyan for me) without any detectable decline in color quality or accuracy.
I'm inclined to think that you're right, although I believe the 7600 doesn't use K3 ink. I just need some assurance from K3 ink users, i.e. those who use R2400, 4800, 7800, 9800 printers.