Data update based on periodical base date data change

[Muthukrishnan V]

Solar query to BB.xlsx
	A	B	C	D	E	F	G	H	I	J	K
1	No, of Units consumed on daily basis based on the Units reading in Col F
2
3	Date	Units	No.of Unit
4					BaseDate	Units
5	14-08-2020	1641.00	161
6	15-08-2020	1645.00	165		21-07-2020	1480
7	16-08-2020	1650.00	170		20-09-2020	1738
8	04-09-2020	1692.00	212
9	13-09-2020	1722.00	242
10	20-09-2020	1738.00	258
11	21-09-2020	1740.00	260	C11 should be 2, i,e. (B11-F7; and not B11-F6) because base date & units changed
12	22-09-2020
13
14
Sheet1

Cell Formulas
Range	Formula
A6:A7,A12	A6	=$A5+1
C5:C12	C5	=IF(B5<=0,"",B5-F$6)
C13:C14	C13	=IF(B13<=0,"",B13-F14)

Data update based on periodical base date figure change

I attach SolarBB excel worksheet in XL2BB.

I post units on day to day basis in Col A and B, to find the number of units
consumed from base date figures in Col E and F.
E and F gets periodically updated once in two months.
Col C calculates the number of units consumed from Col F.

My requirement: When Col F gets updated, Column C calcuation should take
revised date in Col E.

Kindly advise formula in Column C.

Thanking you,