Correcting existing indicator to have the arrows drawn correctly and alerts send correctly

The indicator needs to draw arrows on chart and alert with messages and sounds when

1) the MACDBuffer[i]>0 for buy arrow or <0 for sell arrow

2) MACDBuffer[i]>SignalBuffer[i] for buy arrow and vice versa for sell arrow.

The logics for the indicator is corrected the way it is now.  I don't need to change the logics.  However, the arrows was not drawn when the logics is calling for it to be drawn.  Instead, it only draw only the sell arrow and not the buy arrow or vice versa.  What it does is that after it draws the sell arrow, it went back and re-draw the previous buy arrow.  Basically, the last programmer did not program this drawing of the buy or sell arrows correctly (same for the alerts)

In summary, I would like to have the arrows drawn correctly at the right time (also for alerts).  No repaints.  No re-adding of the arrows to other previous price bars.  Indicator logics are corrected but the arrow's logics (also alerts) are not.