Can S&OP improve service level without inflating inventory?

Yes, and that is increasingly the point. Static safety stock rules force a trade-off: more service requires more stock. Probabilistic buffers, recalculated against demand uncertainty, change the equation by concentrating coverage where risk is real and trimming it where it is not.

Saint-Gobain Sekurit AGR is one example, moving its service level from 95.8% to 97.2% while cutting inventory by 9.25%. The lever is the sizing logic, not the budget.