Replicating Entry Page-Based Workspace Reports with Data Feed

[imh1]

I'm trying to use our data feed to replicate a Workspace report showing all visits with a particular entry page, and I can't seem to avoid getting discrepancies (always a slightly lower value through the data feed). 

I'm pulling visits (counting distinct concat(post_visid_high, post_visid_low, visit_num, visit_start_time_gmt)) for a given post_pagename where visit_page_num = 1 and hit_source not in (5,7,8,9) and exclude_hit = 0.

I also have tried visit_start_pagename, instead of using post_pagename plus visit_page_num, and that gets me just barely different numbers, but no closer to what's in Workspace.