The Superhero Database Classification number, or SHDB Class, is a number that represents the overall 'power' of a character. All traits of a character are used for calculating the Classification.
What it DOESN'T mean
This doesn't mean that a higher class would always beat a lower class character. But the bigger the difference in Class is, the more obvious it is who'll win in a fight.
How is this calculated
( INT^1.3 + (STR*0.5 )^2 + (SPE*0.5)^2 + DUR^1.6 + (POW + (SPS*SPL))^2 + COM^1.8 ) ^ TIER
Super Power Score and Level
Every Super Power has a score (SPS) that is used to calculate the Class. Each Super Power also has 3 levels (SPL). The level is set when connecting that Super Power to a character. The level determines the final score, of the Super Power, being used in the calculation.
DC Ares would win on known differences.
https://www.quora.com/When-compared-to-Darkseid-how-powerful-is-Ares-I-know-Ares-is-weaker-but-how-powerful-is-he/answer/Bob-Joe-1708?ch=15&oid=307828557&share=fbad4e66&srid=uFZLGu&target_type=answer
This is same what @MoNsTeR said where Ares and Darkseid are actually close (even at same level) even though Darkseid is still more powerful than Ares.