Hello mohamedessadouni:
The flashing time should be measured from the moment the command is launched by clearing CCIF (write 1 to clear). Also, the datasheet specifies 65 us as typical, but the maximum time is 145 us.

About programming, for Kinetis L there is no "Program Section" command, so yes, you have to write 32 bits at a time.
Regards!,
Jorge Gonzalez
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