I figured it out!
I put the stationing in backwards. I was thinking left bank obstruction, and to block out an entire left overbank the “starting” station is the one closest to the channel. But when you only want a partial block, the starting station becomes the lesser stationing value.
Correct Example:
Normal Obstruction Mode:
Left Station = 240
Multiple Blocks Mode:
Start Station = 100
End Station = 240
I kept thinking for some reason to put the Start Station at 240 and the End Station at 100. Brain fart. Have a chuckle at my expense.