Replication, backups in parallel mode issues

We had someone originally setup our AVE instance, back in October, and when setting up replication had chose the "Replicate client backups in parallel: option under the "Oder" screen for our Replication Group.  Which they explained was the more efficient method to use. 

So right before the holidays I noticed that some clients had stopped replicating and others had never replicated, some newer clients.  Forcing replication didn't fix it, forcing replication on the client itself in the Policy screen didn't do anything for those clients either, opening the replication window to 18 hours didn't do anything, thinking maybe the replication window was closing too early. 

So I opened an SR and the tech wasn't of much help, so in troubleshooting I reverted back to the "Default Mode" and that made everything start working again, the clients that weren't replicating or had stopped replicating started replicating and everything caught up and is working fine.  Now I'd like to switch back to the "Replicate client backups in parallel". 

What I'm wondering or was hoping someone can tell me is, changing between replication methods, does that cause issues of any sort or just change the method it uses to transfer the data and does turning on VSR and issue or not recommended, it says "...for those plugins designed to use it, wasn't sure if the VMware plugin took advantage of it?  Thanks for any insight.