Is there a simple way to check if a given class need to be recompiled ?

A class (and routine) definition can sometimes differ from it's compiled state.
When such a thing occurs, a "+" sign will be shown in the tab of the file opened in Studio.

I would like to do the same check programmatically.

For routines, it's very simple : 

set routine=##class(%Routine).%New(name)        
write routine.UpToDate

For classes, I could not find the equivalent. The only solution I found so far is to compare the compilation date and definition date :

set classCompiled = ##class(%Dictionary.CompiledClass).%OpenId(name)            
set classDefinition = ##class(%Dictionary.ClassDefinition).%OpenId(name)
write classDefinition.TimeChanged '= classCompiled.TimeCreated

Is there a better,  cleaner way ?
The main issue is that there is no proof that this is what Studio does. It probably use some more complex logic. There is a few cases where I got a "+" and it's undetected (and the opposite).

EDIT: 

Checking the status of the generated classes (.1.int files) helps a little bit : 

set routine=""
for
{	  				
    set timeStamp = classCompiled.Routines.GetNext(.routine) 		  			
    quit:routine=""
    set routineTime = $get(^rOBJ(routine,"INT"))		  			
    write routineTime'=timeStamp
}