What kind of oak? What kind of fertilization were you doing? What percentage of defoliation did you achieve? Is the tree a fast grower or a slow grower? What was the growth like before the operation? Pics? Without that info it would be hard for me to suggest continuing the reduction, but it does sound like you should.
In terms of completing the operation, Ryan was saying that you can’t defoliate one half of the tree and come back to do the other half later. The energy distribution needs to be widespread. Of course leaving select areas untouched with developmental goals in mind as needed.
I will say that my crape myrtle started pushing new growth within 2 weeks. It’s a vigorous tree to say the least which is typical of species.