Compare Date fields in Marketo Smart List

Hello Marketo expert,

We are trying to find leads who has the Date 2 happened after Date 1.

For example: we have "sign up date", "status changed date". We are trying to find those status changed after they signed up.

Is that possible to compare two date fields in a Smart List? Or can we create a new integer field with value filled with "status changed date" minus "sign up date"? Or there is other way around?

Thanks,

Becky