Add a field to basic key figure

Hi SAP community,

We are trying to use a standard field called 'completion date (local)' to create a custom key figure. The reason why we want to specifically use this field is that all other 'completion date' or 'resolved on' fields are in GMT time zone and this local field is the only one in EST time zone. However, this standard field is not available as a basic key figure to use for our calculation.

Do you have any suggestions on how we can add this field to our basic field list? Your help is much appreciated.

Thank you!