How to calculate Planned Work - Actual Work (from RTC) using Custom Expression in Jazz Reporting Service 6.0.6

 Hello,

I have an older (6.0.3) Jazz Reporting Service report that used the advanced features to calculate Planned Work minus (-) Actual Work.  It worked fine, but the report couldn't be modified in the RTC dashboard widgets due to using the advanced feature.  We recently upgraded to Jazz 6.0.6 and finally have access to Custom Expressions in the report builder which is supposed to provide more capabilities without having to use the advanced features in the reporting service.  My question is how can I achieve a calculation of two integers using the Custom Expression without having to use the advanced capability?

For example:

Old Way Using Advanced...

 SUM(T1.PLANNED_WORK-T1.ACTUAL_WORK)/3600.00 AS REMAINING_WORK 

New Way Using Custom Expression....

????????

Let me know if this is even possible with the Custom Expression.

I appreciate any and all responses and thank you for your time in advance.  

This is where I need help, guidance, or