Most IPSI problems come from weak processes, not from the rule itself. With a basic validation and documentation routine, repeated incidents can be prevented.
Mistakes 1 to 3: classification and calculation
The first failures are usually wrong tax classification, outdated rates, or mixed VAT and IPSI logic. A case catalog and explicit rules prevent these deviations.
Mistakes 4 to 5: insufficient documentation
Without documentary support, any review becomes slow and expensive. Keep operation evidence, calculation detail, and the reason for each applied treatment.
Mistakes 6 to 7: lack of periodic controls
Skipping monthly invoice reviews creates accumulated errors. Add sampling checks and pre-close alerts to correct issues in time.
Four-week correction plan
Week 1 define rules, week 2 correct templates, week 3 train the team, and week 4 audit outcomes. This cadence keeps change fast and sustainable.
Next step
If you want a realistic diagnosis for your case, we can help you implement compliance with a phased plan.