Two items of order here.
Item 1: Mile 0 is located
directly north of the customs plaza, at the end of TXDOT maintenance. The southern terminus should thus I would think be here and not at the border, no? Just like with I-69W.
Item 2: the interchange with US 62 has been mostly removed. The only remaining ramp is an exit from US customs directly to US 62, the gore point for which is at or slightly before the location of Mile 0. Since it is no longer possible to enter or exit here and drive on any inch of I-110, I would mark this point as closed.