Device: IGLOO2/SmartFusion2

"Exact Value" sets the tolerance of the generated clock frequency to 0.5 kHz.
Depending on the input clock, it may not be possible to generate the clock frequency according to the Frequency setting you have specified, and the Actual field will display a frequency that is close to the desired frequency within the range that can be generated.

For example, if there is a difference of 2 kHz (0.5 kHz or more) as shown below and Exact Value is checked,
The current settings cannot generate the desired clock, so an error message will appear asking you to review the settings.

For more details, please refer to the URL below.

what does “exact value” mean with Clock Conditioning Circuit GUI?
https://microchip.my.site.com/s/article/what-does-exact-value-mean-with-Clock-Conditioning-Circuit-GUI-1625098140562

Exact value in CCC configuration
https://microchip.my.site.com/s/article/Exact-value-in-CCC-configuration-1625098152016