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.
And darkseid win
^Darkseid getting one shot
Listen Bernardo Darkseid can solo the JL including Superman, Superman doesn't hold back against Darkseid which is stated in the Justice League cartoon which is entirely based on the comics, and if you actually read the Silver Age Justice League books you'd see that Darkseid DID beat Pre Crisis Superman. @Oblivion A: Superman needed multiple sundips to pull that off B: Superman is usually 4th dimensional so a 6th dimensional feat would be an outlier otherwise he'd be more powerful than Mxy which is clearly not the case.