EDIT: I'm not talking about leveling speed or efficiency, my examples below highlight (at least for me) that post DCS the XP curve for prestiging vs leveling a brand new unlock has been incredibly different when pre-DCS that difference didn't exist
I've been running the 'standard' route pre/post DCS with 200% synergy bonus, cyclops XP bonus and 50% pot (260%) for prestiging and this is what i've noticed
Pre-Patch any Hero: lvl 21 after talking to the guy in Chapter 3 - safehouse
Post-Patch prestiging Deadpool (Blue): lvl 18 after talking to the guy in Chapter 3 - safehouse
Post-Patch brand-new unlock of Antman: lvl 26 (!!!???) after talking to the guy in Chapter 3 - safehouse
I always use the cyclops synergy (I'm in a prestiging everyone phase) and always have the 50% pot going. Pre-patch any non-cosmic prestige always put me in the same spot level wise at that point. Now it looks like DCS is effecting XP-gains differently depending on if it's a first-time hero or a prestiged hero.
All the runs I do, including before DCS was added, I pretty much kill all the mobs up to that point (I would usually start boss-rushing after Elektra)....so for the most part I'm doing the same thing, same setups, same paths and same kill-counts as I've always been doing.
This might explain why some people have been experiencing different XP gains after the DCS patch.
The ONLY thing that was different was that for Antman I decided to pop a few more of the 50% pots to increase the duration, but it was on to begin with (i.e. buffs you have running prior to the DCS patch aren't being taken into account until you 'refresh' them)