[amibroker] How to plot lines 10% up and down from zero line of a monthly indicator

[john10987654321]

I have created a monthly ROC indicator and added a zero line to it.

I would like to plot two lines around the zero line, one 10% up from the ROC at 
the zero line and another 10% down from the ROC at the zero line. 

How do I do this? Any help appreciated. 

// Monthly Rate of Change  

TimeFrameSet( inMonthly ); // switch to 5 minute frame 
/* MA now operates on 5 minute data, ma5_13 holds time-compressed 13 bar MA of 
5min bars */ 
MonthlyROC = ROC(Close,10);
TimeFrameRestore(); // restore time frame to original 
// plot 
Plot( TimeFrameExpand( MonthlyROC, inMonthly), "Monthly ROC", colorRed, 
styleLine); 
Plot(0,"ZERO LINE",colorBlack,styleThick);
_SECTION_END();