The CUET scale and normalisation
Each subject paper in a mock is marked on the CUET scale, out of 250, so your mark reads the same way a CUET score does.
In CUET, a subject paper is often held in more than one shift. When that happens, NTA may normalise scores so that candidates in different shifts are compared fairly. We don't guess at that step. For each CUET year we use the score–percentile data published or verified for every subject, so the percentile you see follows the method NTA used that year.