This VEX Function could be an alternative for Attribute Promote.
//Run over Detail Mode
//Get Arrays Value
float val[];
int npoints = npoints(0);
for (int i = 0; i<npoints;i++) {
float data = point(0,'value',i);
push(val,data);
}
int totalIndices = len(val);
f[]@val =val;
//Start Finding Max Min
float min,max;
min = val[0];
max = val[0];
for (int y = 0;y<totalIndices;y++) {
if (min > val[y]) {
min = val[y];
setdetailattrib(0,'min',min,'set');
}
if (max < val[y]){
max = val[y];
setdetailattrib(0,'max',max,'set');
}
}
If you find much better algorithm, Please let me know. I hope that gonna be useful to you.