This is only a thought and I don’t know if it will work, so you’ll need to test out the theory.
You could put the values from the ACF form submission into a SESSION value or some other persistent value. To do this you would create an acf/save_post filter http://www.advancedcustomfields.com/resources/acfsave_post/
Then to load the last values into the form when a new form is loaded you can use an acf/load_field filter. http://www.advancedcustomfields.com/resources/acfload_field/. The example shows changing field choices, but this can be used to change any ACF field argument. You can use this filter to change the default value of the field to match the last saved value.
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