Update Oct 7, 2021 We ended up going with iTools. Small, lean, effective business. I had no affiliation before seeking them out to solve this problem. Super impressed with the customer service. They bend over backwards for their customers. https://appexchange.salesforce.com/appxListingDetail?listingId=a0N30000001gFEWEA2
Rollup Helper was less expensive, but too basic for our needs.
I received this from my Salesforce Success Manager: Account Hierarchies are created through Lookup relationships in Salesforce. Because of that, it's not possible to use standard roll-summary fields to create cross-account roll-up values. That said, there are a lot of great resources available through our Success Community and from advanced admins that I think may help: Steve Mollis' "Ultimate Parent" formula and reporting tip: https://trailblazers.salesforce.com/answers?id=90630000000ChkPAAS Andy Fawecett's open source package available on Github for declarative rollup lookup summaries: https://github.com/afawcett/declarative-lookup-rollup-summaries#packaged-release-history AppExchange solution from Passage Technology (Rollup Helper): https://www.passagetechnology.com/rollup-helper-use-cases/2014/4/30/eydpg6v602ttc2uacdezcs0i40jyh6