Try either of these two:
a. Put a submaster FX on the mixdown track. Step into it and apply your DVE.
b. Don’t mixdown (you have an original copy of your sequence, right?). Open 1 title, promote it to 3d, make your changes. ALT/Option drag the FX icon in the upper right hand part of the window to a bin (it will have the ‘without source’ suffix added). Select your titles using segment mode (there is an easier way, but I don’t remember it at this time of the morning!) by shift clicking. Double click your FX icon in the bin. Voila’!
HTH –
Jon
“The Almighty tells me He can get me out of this mess. But He’s pretty sure you’re F%$#*D!”