For part number ICX7250-48-2X10G:
Description: 48-port 1 GbE switch bundle with 2x1GbE/10GbE + 6x1GbE SFP+ (upgradeable to 10GbE) uplink/stacking ports upgrade
Notice that keyword "to" (highlighted). You must have the 2x10G before you can apply the 8x10G license. That really should say 6x10G, and can be a little confusing. I hope this clears up any confusion.