The Powerful and Easy-to-Use Desktop Calculator for Real Estate Investors and Agents The Qualifier Plus IIIfx-DT is the ideal tool for real estate investors and agents. In addition to both common and advanced real estate finance problems and complete buyer qualifying, it calculates multiple cash flows and internal rate of return (IRR), as well as net present and net future values (NPV/NFV) - all in a large, easy-to-use desktop format.