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.
Doctor Doom might have an advantage over Immortus in terms of raw power and versatility, as he can combine his scientific and magical abilities to create devastating attacks and defenses. He might also have an edge in terms of cunning and determination, as he is willing to use any means necessary to win.
Immortus might have an advantage over Doctor Doom in terms of temporal and spatial control, as he can manipulate the flow of time and the fabric of reality in Limbo. He might also have an edge in terms of knowledge and experience, as he has lived for thousands of years and studied the secrets of time and the multiverse.
Based on these factors, I think the outcome of a battle between Doctor Doom and Immortus would depend on the circumstances and the location of the fight. If the fight takes place in Limbo, Immortus might have the upper hand, as he can use his temporal and spatial powers to his advantage. If the fight takes place in another dimension, Doctor Doom might have the upper hand, as he can use his scientific and magical powers to his advantage. However, both of them are formidable opponents, and the fight could go either way. It would be a close and epic battle, that is for sure.