Metatrader indicator minor amendment

I have a simple indicator (only 40 lines of code) that creates a sub-window of the closing price over the last x defined bars within a scale of 0 - 100. I want to amend the code so that instead of referencing the closing price on a chart it can use the output from another indicator using iCustom(other indicator). It currently uses:- iBarShift(NULL, tf, Time[li_0]); iHighest(NULL, tf, MODE_HIGH, barcount, li_4); iLowest(NULL, tf, MODE_LOW, barcount, li_4); iHigh(NULL, tf, li_8); iLow(NULL, tf, li_12); and then a simple formula to calculate the line:- gda_88[li_0] = 100.0 * ((Close[li_0] - ld_24) / ld_32); I need it to be amended so that it can find the highest high & lowest low of another indicator value over the last x bars and perform the same calculation so that it creates a line that oscillates between 0 & 100. Maybe there is a way to exchange the Symbol / NULL reference for an iCustom formula. It just needs reworking so that I can enter the other indicator into iCustom in the correct place to get the correct output. Should be a quick $30 for someone in the know !