Could you elaborate what you mean by the current setup missing some points?

You have 7-digit numbers and appear to be rounding to the third digit. The node you are using gives you Floor and Ceiling rounding methods, it looks like you chose to use RoundUp (or Ceiling).

This means that:
001 β 100
050 β 100
099 β 100
101 β 200

Thank you for your response - Examples which you gave are quite correct.
i want only x points of each point to be rounded so that i have proper groups,

The above points are centroids of Surfaces - i am taking the centroids so that i can pick the elements row by row like in groups

points needs to be sorted with x values and then grouped , as you see not all rows have center points same , tiles in the edges have center points with x diierence in x values,

i was trying to round them up and then group as per the image shown above ,
My solution above works , yet does not hold good for all conditions