Need some guidance on Deferred Revenue Waterfall report - what does the date filter "As Of" mean? When we run the report, the totals don't match up with our other financial reports. And what dates/periods do the "Thereafter" column consist of?

As of should be the same 'as of' the balance sheet uses, i.e. the report is showing info through that date. If it doesn't match your other reports, you have a problem somewhere. The Thereafter column is just a summary of any period after the last months of your revenue plans. Meaning I think the report has a limit of showing 12-24 monthly columns. But you may have plans that go longer than 24 months. So instead of showing columns for month 25-x, the reports just lumps everything else into that single column.