@urvashimanani - ‘Time spent per visit’ dimensions record the amount of time a visitor spent on the entire visit.
However you should try using Dimension ‘Time spent on page’ . It records the amount of time a visitor spent on the page.
Could you please share more details on this like segment is based on Hit, Visit or Visitor level container? Please share the segment definition.
time spent per visit is based on Visit level. If you apply a segment on visit level there would hardly be any difference.
If you apply the segment based on Hit level with page conditions, data will change.