Originally there were two points here for the 16th Avenue and 80th Street exits. When IA 100 came in, because it used the original EB exit ramp, I left that as 246 so as not to break things, but also added a 246A for the new exit from WB 30 because it was half a mile to the east.
I could collapse 246 and 246A into a point that is closer to midway between the ramps while moving 246B westward.
Was anybody using the 'original' 246 before IA-100 arrived?
I see how they reused the ramps looking at historic aerials. In this case, to me, you could say that since they repurposed the ramps, and added the WB movements, a center between the ramps would be justified here as '246A'. Especially since they added the missing movements @ 80th Street making that a complete interchange separate from the other one.
Now, if you still want to keep the 'old' 246, you could possibly. Just mark it as '*246'.
Here's how I'd setup the area personally after seeing the historic aerials and if I kept the 'closed' exit:
*246 http://www.openstreetmap.org/?lat=41.963312&lon=-91.788781
246A http://www.openstreetmap.org/?lat=41.961828&lon=-91.780901
246B http://www.openstreetmap.org/?lat=41.957938&lon=-91.774737