The behavior of Simulink block Compare To Constant boggles my mind !
It doesn't work for the particular value 268.03 but works for other values such as 15.68 as shown below. And I really don't understand why is this the case.
For now, I'm able to do what I want by using strings instead as shown below:
I still want to understand why the simple Compare To Constant block doesn't work for this particular value (maybe others too that I'm not aware of...).



Thanks to @Wolfie's comment I was able to make the model work.
where the code inside the Matlab Function block is as follows: