Настройте данные следующим образом:
|A |B |C |D |E |F |G |H |I
1|Item |Start |End |Duration|Value|01/07/2017|01/07/2018|01/07/2019|01/07/2020
2|My Subscription|01/04/2018|31/03/2019| |3500 | | | |
Со следующими формулами:
D2 =YEAR(C2)-YEAR(B2)+(MONTH(C2)-MONTH(B2))/12+(DAY(C2)-DAY(B2))/365
F2 =$E2*IF(AND($B2 >= F$1,$B2 < G$1),IF(AND($C2 >= F$1,$C2 < G$1),1,(YEAR(G$1)-YEAR($B2)+(MONTH(G$1)-MONTH($B2))/12+(DAY(G$1)-DAY($B2))/365)/$D2),IF(AND($C2 >= F$1,$C2 < G$1),(YEAR($C2)-YEAR(F$1)+(MONTH($C2)-MONTH(F$1))/12+(DAY($C2)-DAY(F$1))/365)/$D2,IF(AND($B2 <= F$1,$C2 > F$1),1/$D2,0)))
^Copy this across to G2 and H2
Это в значительной степени взято из: https://www.mrexcel.com/forum/excel-questions/563602-split-value-across-fys-based-start-end-dates.html