Here's a weird one: AR I-430.
The end was signed as Exit 129 all the way back, formerly just labeled I-30, Nebraska-style.
It already had an Exit 1, and rather than add Exit 0 or get into more alphabet soup for Exit 1 or even 129, ARDOT chose to add Exit 128.
Needing 128(30) now, there's not much justification for keeping I-30 rather than 129(30).
And on the other side of the Little Rock metro, you have
I-440 using Exit 138 from I-30 while I-530 uses Exit 1. Additionally, I-630 uses Exit 1 for a ramp that doesn't intersect I-30 while using 139B&C for the ramps that do intersect I-30 (
why do you hate Exit 0 Arkansas). It seems like this is Nebraska and Arkansas' way to avoid using Exit 0s (although Arkansas is very inconsistent).
Meanwhile, in Memphis, I-40 starts out with a bunch of suffixed Exit 1s then starts a sequence that continues onto I-240 while I-40 takes over the Sam Cooper Boulevard numbers (
here, probably a holdover from when Sam Cooper was supposed to be I-40).
I think overall for these now 6 cases (I-180 NE, I-480 NE, I-680 NE, I-440 AR and I-630 AR), the ##(XX) format seems to fit this to a T, since that's what anyone will see from the road (would avoid the question of "I thought this was Exit 401, why does the HB just say "I-80"?) and it's an exit number sequence from another exit numbered road.