Reproduction steps:
1. Open the user's attached project
2. Right-click on Assets > Textures > Test folder
3. Select Reimport
4. Open Editor.log and observe import time
5. Open Project Setting > Editor settings and enable the Parallel Import setting
6. Change "Desired import Workers Count" to 2 and "Standby import Workers Count" to 2
7. Repeat steps 3 and 4
8. Change "Desired import Workers Count" to 4 and "Standby import Workers Count" to 2
9. Repeat steps 3 and 4
10. Change "Desired import Workers Count" to 8 and "Standby import Workers Count" to 2
11. Repeat steps 3 and 4

Expected result: Import time is faster
Actual result: Import time is slower

Reproduced with: 2021.2.3f1
Not reproduced with: 2021.2.4f1, 2021.2.6f1, 2022.1.0b2
Could not test with: 2019.4.34f1, 2020.3.24f1 (no Parallel Import setting)