I think Janat was complaining that their King ordered NS on half chained enemies, which is unwise unless the chainee in question released all his thieves..
Im pretty sure there is no GBP on ops, but as Bo To says - the damage reduction is due to reduced resources.. In Janat's case the problem is prolly inflated tpa from chaining, and the reduced nw making the rpnw diff cancel out any real gains, and ofc the loss of thieves due to heavier failure..