ECC+ and Akeeba Engage

Hello.
I would like to add {easycalccheckplus} in the comment form Akeeba Engage. I created a template override and activated the Custom call parameter in the ECC+ plugin but the {easycalccheckplus} text appears as on the page, just before the Submit button.

I also tried with an alternative search string but the code remains as what and the plugin is not called.
How do you do, please?

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