This SQL returns what I want. Is it the most efficient way? (It assumes that we can not have two same statuses at the exact same time for one Trans):

text TO lcSQLStr TEXTMERGE noshow
SELECT cCode_Description as cStatus, ;
CAST(SUM(NVL(IIF(BETWEEN(Trans_Status_Codes.tAs_Of_Date,##START_DATE##,##END_DATE##),1,0),0)) AS I) ;
as iOriginal, ;
CAST(COUNT(Trans.cTrans_pk) AS I) as iCurrent ;				FROM MMVisCollect!Trans ;
	INNER JOIN MMVisCollect!Trans_Status_Codes ;
	ON Trans.cTrans_pk = Trans_Status_Codes.cTrans_fk ;
	INNER JOIN MMVisCollect!VisCodes ;
	ON Trans_Status_Codes.cStatus_Codes_fk = VisCodes.cVisCodes_pk ;
	INNER JOIN (SELECT  ;
	cTrans_pk, MAX(tAs_of_Date) as tMax_Date ;
	FROM MMVisCollect!Trans ;
	INNER JOIN MMVisCollect!Trans_Status_Codes ;
	ON Trans.cTrans_pk = Trans_Status_Codes.cTrans_fk ;
	INNER JOIN MMVisCollect!VisCodes ;
	ON Trans_Status_Codes.cStatus_Codes_fk = VisCodes.cVisCodes_pk ;
	WHERE Trans.iBatch_Number = <<m.tiBatch_Number>> ;
	AND VisCodes.cCode_Description LIKE "NAME SEARCH %" ;
	group BY cTrans_pk) AS Max_Status ;
	ON Trans_Status_Codes.cTrans_fk = Max_Status.cTrans_pk and ;
	Trans_Status_Codes.tAs_of_Date = Max_Status.tMax_Date ;
	WHERE Trans.iBatch_Number = <<m.tiBatch_Number>> ;
	AND VisCodes.cCode_Description LIKE "NAME SEARCH %" ;
	GROUP BY 1					
ENDTEXT
lcSQLStr = strtran(m.lcSQLStr, '##START_DATE##', m.lcStart_Date)
lcSQLStr = strtran(m.lcSQLStr, '##END_DATE##', m.lcEnd_Date)