Hans, otero pump station doesn't impact roberts tunnel flows. Otero is operated by Aurora/CO springs. My understanding is that Otero pulls directly from the ark river. Here is some more info on otero etc.
USGS Colorado - Upper Arkansas River Basin
Moffat tunnel pulls from the frasier river basin around winter park and dumps into south boulder creek. Denver water uses this water, but I talk mainly to the guys that work with roberts tunnel, so I don't deal with the moffat system much.
The colorado water systems are complicated, and you can learn a lot about them by spending some time on google looking at maps and descriptions.
Yes I do think you misinterpreted that water released from lake dillon into the blue goes to the east slope. Dillon was built by denver water (I think) as part of a deal to get blue river water to Denver. Denver does not have rights to all of the water, so some of it flows down the blue and eventually into the colorado. I think denver water operates dillon and sends the water downstream or into the tunnel as needed.
If you want to do some research on it... Look at denver waters internet pages that explain their system, look at the colorado big thompson project to explain what the bureau of reclamation does for diversions. Also look at the arkansas fryingpan project. These are the big players in west to east diversions. There are diversions on the poudre too.