Hi
You can try to use below formula if it works on your side:
Total of last month =
var currDate=MAX(Tempo[Date])
return
SUMX(FILTER(ALL(Tempo),currDate>= DATE(YEAR(currDate),MONTH(currDate)-1,1)&&currDate<=DATE(YEAR(currDate),MONTH(currDate),1)-1),[VALUE])
Regards,
Xiaoxin Sheng