Level of classification can differ between agencies it is true but it obviously has to be there in some form since the SoS cannot do their job without top secret information.
Classification levels and modifiers are uniform across the Federal govt. What may differ is OCA judgement as to what is confidential, secret, TS, SCI, etc.
I watched the Democrat "Town Hall" on Fox News Channel last night. Once again, Hillary played her little word game, saying "I never sent or received any messages marked classified." Technically, she's correct - because there is no security marking that would be identified by the word "Classified." Classified is a generic term that encompasses specific levels of classification such as Confidential, Secret, and Top Secret. Someone needs to spell this out for her, then ask her point blank if she ever sent or received any messages marked Confidential, Secret, or Top Secret.