A forecasting method that responds slowly to changes in demand would be most appropriate when...

If demand is relatively stable and has only minor random variation, a stable or slow-responding forecasting method, such as a moving average with a long period, is best. Fast-responding methods are prone to overreact to noise in such cases.

“Slow-responding methods are preferred when random variation is small and stability is desired in forecasted outputs.”

— CPIM ECO Module; Forecasting Techniques Section