Seems like I may have answered my own question, or at least half of the question. I found a few reports that were working as expected and another one that wasn't.

After comparing the differences, the ones that were working had the report column set to pull data from a database column that was an integer. As for the one that wasn't working, the data was being placed into a temp table for more complex calculations and queries but the columns that these integers were placed in where varchar columns. We switched the temp table columns to integers and these came across correctly into Excel.

However, since we're still on SQL 2005 the date doesn't work so well since it's datetime and not just date. Has anyone figured out how to make dates work for exporting into Excel to be used in analytics/pivot tables?