Matt, I've been running RA4 through a Printo since RA4 came out.
I only have two energy Mot units, so obviously I run the dev in the first bath and the Blix (BLeach fIXer) in the second.
As the exit rollers are squeegee rollers, and they do a good job, there is only nominal carry over to the Blix.
The Blix has close to double the capacity of the developer. I have never had the Blix go off before the developer. In fact the developer will exhaust well before your Blix.
You could of course run an extra bath, it will certainly let the Blix last a bit longer, however there is also a time limit of just how long a Bleach/Fix will last once it is mixed up. So unless you are putting mega pieces of paper through, it may not be worth it!
Mick.