Isfirstoccurrence - Argument for whether to consider Case-Sensitivity

I think it would be a better option to have as a model builder. Currently, Isfirstoccurrence deals with Case-Sensitive data as separate occurrences for eg. NA and na would both be seen as separate occurrences. There are many cases where, as a model-builder, You don't want this to happen. So, having an argument to confirm case sensitivity while using Isfirstoccurrence would be great.