Repeat member suppression was the fix.

Tim,

Thanks for jogging my brain. After working the SR and reading the blog posts on this topic for the umpteenth time I realized I wasn't suppressing repeat members. That resolved my issue.

It is still not quite as fast as the classic add-in but it is pretty close (I'll have to run some benchmarks to know the full impact) and given the better feature set of SmartView it more than makes up for the slight bit of a performance hit.

Here is an interesting side note though...

I didn't realize repeat members weren't suppressed because given the nature of the data drills that I am doing each row returned is unique. So even though the suppressing of repeat members didn't make a difference in the resulting excel grid it must alter the way the xml is built inside of provider services.