I think I got it.
aggregator.displayformat=HTML
aggregator.function=AVG
aggregator.namekey=datevariance
aggregator.valueexpression=ROUND(DATEDIFF($$TODAY,{entryDate}),2)
aggregator.valueformat=HTML
description=Aging Tickets
displayname=Aging Days
textmode=true
valueexpression=IF({status}="INP",ROUND(DATEDIFF($$TODAY,{entryDate}),2),IF({status}="NEW",ROUND(DATEDIFF($$TODAY,{entryDate}),2),ROUND(DATEDIFF({actualCompletionDate},{entryDate}),2)))
valueformat=HTML