Stochastic and AC in different dimensions - thay scaled differently (Stoch 0-100; AC -from -minus to plus distance of AO and signal - all depends on pair volatolity - market conditions ...); any new AC peak will resat (move) AC zero line (by default - AC autoscaled)

so - to match AC zero and Stoch level 50 (no way zero, off course) - you have to reset AC max/min each chart screen on each TF on each currency...
4example - put RSI and MACD in one window, scroll back and force and look how they "rob" against each other - cross been here, slight market move or your mouse move - and cross gone to other place...

so compair Stoch to Ac levels - its compare apples to oranges - find other, more reliable criteria - as AC crosses zero level, Stoch - over 30 (over 40, 50 60; K,D?) ...