solved this issue -
multiple remote readers -
set 1 fixed fallback - best reader with 100% ecms (and enable 2 fallbacks at a time) - let it choose the 2nd one.
enable force reopen
give best readers bigger weight (may not make a diffrence in lb mode 2)
put the ones that couldn't decode the caid very well in another group (by running lbmode 10 to check stats for a while)
lb_mode =2 (cycle through readers, but if goes above 2500ms for ecm then fallsback to a good reader)
works like a dream