It's in the catalog Mwccwi listed, pg. 30. If you do not have a WPS and have not tested certain combinations of equipment settings, then that is quite a bit to expect out of your operators. They just pull an arbitrary time/pressure/heat setting? Not to mention tip diameters for given gauges. You probably see an inconsistant product. These manuals do give alot of this information. If you don't have any I think it would be a must. The equipment manufacturer manuals are excellent as well. Now this has been a few years since I've been involved with resistance welding but I believe the best one I ever found was made by "Logan", but I can't find them on-line. Maybe that wasn't their name, hopefully some else can shed a little more light. Tuffalloy has some ok publications. Your distributor should be able get these if you don't already have them.