Personally, all I would count on Itel for is to let you know the siding is either still available or it isn't. Aside from that, I would trust my own eye more than I would Itel.
I would question there is a match for the present color as I'm sure your siding has faded. It would be a fluke. There may be something out there that is "close enough" that the eye would not be able to tell the difference after it has been on for a few months. As the Homeowner, that is solely up to you to decide if you're satisfied. However, if you're not, that is no guarantee that your insurance will agree to pay for "matching".