Excel - Sum cells down until identifier
Solution 1:
In cell B2, enter formula :
=SUM(B3:B$18)-SUMIF(A3:A$18,"<>",B3:B$18)*2
Edited
or ,
=SUM(OFFSET(B3,,,MATCH(1,FREQUENCY(1,N(A3:A$18<>"")),0)-1))
then, copied and pasted to B6, B15, and B17
