What independent SI oversight actually checks

Systems integrator fees run 40 to 60% of total implementation cost, ERP Research reports, which makes the SI the largest line item in most ERP programs and often the one with the thinnest independent check. The client signs the statement of work, then largely takes the SI's own word for whether the work inside it is on track. Oversight is the practice of putting a second, independent set of eyes on that work as it happens, phase by phase, rather than finding out at go-live.

Design phase: watch the fit-gap decisions, not just the schedule

Design, sometimes called the fit-gap phase, typically runs 10 to 20% of total implementation hours, ERP Research reports, but it sets the shape of every phase after it. Every gap the SI proposes to close with custom code instead of standard configuration is a decision with a compounding cost, and it is far cheaper to question that decision in design than to unwind it in test. Independent oversight at this phase means reading the fit-gap log itself, not the SI's summary of it, and asking why each custom item could not be met with configuration.

Build and test: track the defect trend against the mock-load schedule

A tier 1 implementation commonly runs 12 to 36 months and a tier 2 implementation 6 to 18 months, ERP Research and Sysgenpro report, and most of that calendar sits inside build and test. This is the phase where the SI's own quality gates matter most, because a gate that waves through a defect backlog or a thin mock-load schedule is the gate that produces a rough go-live. Oversight here means reconciling the defect trend against the mock-load calendar directly, every week, rather than accepting a gate sign-off at face value.

Cutover and the weeks after: the dual-run window is where cost hides

A dual-run period, old and new systems both live and both paid for, commonly runs 12 to 24 months, costbench reports. Every week that window runs longer than planned is a week of double-running cost that rarely shows up as a single line anyone questions. Oversight through cutover means tracking the plan to retire the old system against the actual date, not the date in the original statement of work.