Does the retro pay process condense like rows when moved to paylines?

Hi all - looking for some knowledge around retro pay processing. We are currently processing retro pay for a group of employees going back to 4/1. As imagined, this created many, many rows of data. Some employees have 200-300 rows, but when they appear on paylines, the number of rows is much less.

The total dollar amounts seem to match, so we are just most curious as to what is happening behind the scenes.

Thanks!

Casey Darrow