Wait Time for S3 Account Import changes to be Available in the UI

I make bulk changes to account attributes using the S3 Account Import at least weekly, sometimes more than once per week. Every single time, I see the following behavior:

1. S3 Account Import status.txt shows n updated records/successes, no errors
2. nothing in the PX UI reflects any of the changes (not Account Explorer, Query Builder, etc.)
3. I can GET from the REST API and confirm that all of the changes were applied to the data
4. after 15-20 minutes, the table in Account Explorer still does NOT reflect any changes, but if I drill down to the user level, the individual user profile tabs (user or account attributes) begin to reflect the data modified using the S3 Account Import. This is gradual over 15 - 30 minutes.
5. Account Explorer never reflects the data modified using the S3 Account Import any sooner than an hour later, and very typically it’s about 2 hours before we see data modifications in the Account Explorer table

So my question is, what is the expected wait time for S3 Account Import changes to be available in the UI?

If this is the expected behavior, what is the use case for bulk data updates that aren’t usable in the UI for 2 hours?

If the issue is caching for speed’s sake, can’t we engineer a cache dump when the S3 job completes?

Again, I’ll note that this is not a one-off thing I saw on a single occasion; this is the way PX is engineered, and it always takes at least an hour (usually 2)  before we see S3 Import data modifications in the Account Explorer table.