@Tullio ******
nope, it doesn't work like that.
You're confusing a how a 90 day single entry visa and a year-long multi-entry visa work.
You got a single entry 90 day Non-O visa. It's good for one entry of 90 days, period end of story.
All a re-entry permit would do is let you leave/come back during that 90 days and get you stamped back in for the original expiration date.
It doesn't add any days to your admitted until stamp.
you needed to buy a year-long multi-entry Non-O visa from the get go. there's no way to add time to the 90 day single entry one you have other than by getting a yearly extension of stay.