You can edit the fermentation schedule for the recipe, independant of the assigned profile. On the "fermentation" page of the recipe, click the "check mark" next to the fermentation profile. Any changes you make on this page will only apply to the current recipe. Assuming that you are using the brewlog feature, this will record the actual schedule used for this batch.
This section includes a "notes" field at the bottom of the page, where you could add comments with date-codes to record your SG readings.
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