Bus add-ons on the Midleton line
 

From this on the Bus Eireann website, it looks as though a combined Midleton and Cork City bus services ticket is now available.

Strangely, for the monthly tickets, the Cobh ticket is €83 for just the train and €100 for train/bus, while Midleton is €92 for just the train and €115 for train bus.

I'm not sure why the same bus add-on on the Midleton line is €6 more expensive than from Cobh.

Is Irish Rail planning on selling the Midleton/Cobh daily tickets? Not that it's worthwhile unless you're planning on using 3 buses in the day from Midleton or 4 in the day from Cobh.

Rail fares to Midleton are higher than those to Cobh, hence the difference

But wouldn't that already be in the rail portion of the ticket?

To get a bus add-on from Cobh costs €100 (Bus + Rail) - €83 (Rail Only) = €17

From Midleton it is €115 (Bus + Rail) - €92 (Rail Only) = €23

So you pay €17 extra for access to the Cork City Bus Service from Cobh, but €23 extra from Midleton. And it's exactly the same service that you're entitled to.

Might it be so that Midleton doesn't get a fare rise in January?

It may be that Midleton people (origin or destination) might be more likely to use the bus more often as Cobh people will use the ferries to Haulbowline and Passage West to get to Ringaskiddy.

The Bus Éireann Suburban services zone (different from their City Services zone) is rather oddly shaped.