Most western ECM / eccm systems basically have 2 modes : a "training" one, which is used during exercises ... and a "War" mode, the purpose being not to give all info top potential ennemies or competitors
example : during the redflag exercises between french and the US, because both may compete in selling some aircraft, they tend to "hide" some specificites
So, of course, when a system is defeated, the answer is "we did not use it up to full capacities"
Additionnally, yes, there are a lot of variants and costumization among users.
For instance, during Iran / Iraq war, the french ecm pods used by the Iraqi were customized to speciifcally adress the Iranian (US bought) defenses, which were very different from their expected ennemies (warsaw pact in Europe)