What time is used for reporting SKAdNetwork-source data?

The time used in reporting SKAdNetwork activity is the time at which the SKAN postback is received. Since this activity doesn't include an install or conversion timestamp, there's no way to accurately assess when these actions happened, so these reports use the received time instead.

This means for the date range you have picked, you're seeing the activity received within that timeframe rather than what actually occurred during it.