I have seen and reported a specific example of a publisher who was showing different results for the same title (retrieved on the same day) for the tabular vs SUSHI and it came down to that the report was somehow splitting the title across two different DOIs and the other wasn't (and this was happening for multiple titles in that report).
It's not a general problem - I have spent many hours in the last few months comparing SUSHI and tabular R5 reports side by side and this problem is very rare and very idiosyncratic to specific platforms and even specific titles within platforms.
What you need to do is report the specific instances you find to the platform/vendor/publisher in question so they can fix it.
The key is to be very specific in reporting the problem, not just the way you described it so vaguely here, but explain exactly which report, which time period, and which titles/lines in the report demonstrate the discrepancy.
Otherwise no one can do anything with your complaint.
Separately from that kind of error, vendors do sometimes admit that data they released in the past was miscalculated and advise their customers to re-run the reports for a given time period. I've seen that happen for both R4 and R5 over the last few years. There's nothing you can do about that proactively, but just make sure you're on the customer service announcement email lists for all of your vendors. I have raised the possibility with Project COUNTER of them maintaining some kind of centralized announcement list for all COUNTER-compliant vendors (analogous to the Journal Transfer Digest list) to alert librarians to such problems, and it's under long term consideration.
Melissa Belvadi
Collections Librarian
University of Prince Edward Island
ORCID iD: 0000-0002-4433-0189