Я закончил тем, что нашел решение для этого. Это не поддерживает отношения, но это работает.
Totals Table =
UNION(
SUMMARIZE(Sheet4,"Cost",SUM(Sheet4[January 2020]),"Month","January 2020"),
SUMMARIZE(Sheet4, "Cost", SUM(Sheet4[February 2020]), "Month", "February 2020"),
SUMMARIZE(Sheet4,"Cost",SUM(Sheet4[March 2020]),"Month","March 2020"),
SUMMARIZE(Sheet4, "Cost", SUM(Sheet4[April 2020]), "Month", "April 2020"),
SUMMARIZE(Sheet4,"Cost",SUM(Sheet4[May 2020]),"Month","May 2020"),
SUMMARIZE(Sheet4, "Cost", SUM(Sheet4[June 2020]), "Month", "June 2020"),
SUMMARIZE(Sheet4,"Cost",SUM(Sheet4[July 2020]),"Month","July 2020"),
SUMMARIZE(Sheet4, "Cost", SUM(Sheet4[August 2020]), "Month", "August 2020"),
SUMMARIZE(Sheet4,"Cost",SUM(Sheet4[September 2020]),"Month","September 2020"),
SUMMARIZE(Sheet4, "Cost", SUM(Sheet4[October 2020]), "Month", "October 2020"),
SUMMARIZE(Sheet4,"Cost",SUM(Sheet4[November 2020]),"Month","November 2020"),
SUMMARIZE(Sheet4, "Cost", SUM(Sheet4[December 2020]), "Month", "December 2020"))