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.
Alien X is above at least 2 extra dimensional beings (5D), those being Hugo and The Contemalia. Hugo was described as extra dimensional by Professor Paradox and Alien X is above him. The Contemalia are stated to be fifth dimensional and Alien X is above them. A fraction of Celestialsapien DNA is shown to cut through a barrier, the Contemalia (5D beings) described as "extra dimensional" and "impossible to breach" with ease. Alien X was able to recreate a universe efforlessly.
Hyperverse level: The Chrono Navigator is stated to be able to destroy all of existence which includes at least 26 dimensions. Alien X scales above the Chrono Navigator because Professor Paradox who holds it stated himself that Celestialsapiens and Alien X are omnipotent and they have the greatest power in the universe above himself and the Chrono Navigator. Many others have also stated that Alien X and Celestialsapiens have the greatest power in the universe, are omnipotent and is above the Chrono Navigator. Alien X was stated by Servantis to be able to wish everything out of existence which would again include at least 26 dimensions.
Higher Dimensions:
Ben 10 contains 26 spatial and temporal dimensions as confirmed by the Naljins and Professor Paradox. Like I said earlier sometimes the universe gets called dimensions and even sometimes timelines but we should always know which ones which ones depending on the context and situation. In this case we know The Naljins are talking about dimensions in the spatial and temporal sense because she asks Ben if they can only perceive 3 dimensions which lines up with Ben's, Gwen's and Kevin's dimensionality (In the spatial temporal sense). This also lines up with Professor Paradox stating that the Ben 10 omniverse runs on Quantum Mechanics and String Theory. Now there are multiple types of string theory such as Bosonic String Theory which entails that there are 26 dimensions in spacetime, Superstring Theory which entails there are 10 dimensions in spacetime and Supergravity and M-Theory which entails there are 11 dimensions in spacetime. So we can disregard Superstring Theory, Supergravity and M-Theory because they contain to little dimensions to what's stated inverse and we can say that the Ben 10 spacetime runs on Bosonic String Theory. This is quite literally on the money, so the Naljins and Professor Paradox statements support each other. More support that it is Bosonic String Theory is Azmuth stating that the Map of Infinity extends through 17 dimensions which also throws Superstring theory, Supergravity and M-Theory away but the map of infinity is also stated to be a complete map of spacetime, so it's likely Azmuth just doesn't know there are more dimensions or just misinformed one way or another. (Likely only 26D rather than 26D+ from the Naljins implication due to Professor Paradox saying the cosmology goes by string theory which caps out at 26 dimensions and wouldn't go any further. Also Professor Paradox would be the more reliable source as he never lies and has complete understanding of space time)
We don't really know anything about these extra dimensions and how they look but we do see extra dimensional characters or characters from higher dimensions which include: Hugo (As the time accelerating creature), The Contumelia and The Naljins.