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.
On the other hand, Michael Demiurge is the most powerful fallen angel of all time, and is regarded as one of the most powerful beings in the DC universe. He possesses energy manipulation abilities, reality manipulation, and telepathic and telekinetic powers. Also, he is immune to any kind of pain or injury.
However, based on the characters' deeds, I believe the Beyonder would have a slight advantage due to his ability to manipulate reality and his limitless power.