Formula every time a running total column has a multiple of 10

[C_merr]

I need help trying to figure out how to get calculate the average price of ZS every time the quantity column reaches a multiple of 10 (running total) for corresponding ZS rows only. In this example calculate average price of ZS at I9,I12,I17, I20(only the first a quantity of 2 from that price so that it will complete the multiple of 10), I23. I would only like the calculation to occur if it is not going to be the same value as the calculation the previous quantity of 10. (Only focus on the "Real price" not the "Price" because the software that gives out the summary that paste into this template shortcuts prices for ZS so i made a formula to change that back.) Thanks in advance!

Excel 2012
	B	C	D	E	F	G	H	I
8	Contract	Price	BuySell		Quantity		Real Price	Crush @ fill
9	ZS	10652	Buy		10		10652.5	122.8
10	ZL	3124	Sell		9		3124
11	ZM	3838	Sell		11		3838
12	ZS	10680	Buy		10		10680	Calculate
13	ZL	3124	Sell		9		3124
14	ZM	3838	Sell		11		3838
15	ZS	10676	Buy		1		10677.5
16	ZS	10680	Buy		7		10680
17	ZS	10682	Buy		12		10682.5	calculate
18	ZL	3124	Sell		9		3124
19	ZM	3838	Sell		11		3838
20	ZS	10692	Buy		10		10692.5	calculate
21	ZL	3115	Sell		9		3115
22	ZM	3830	Sell		11		3830
23	ZS	10694	Buy		10		10695	calculate
24	ZL	3115	Sell		9		3115
25	ZM	3830	Sell		11		3830
Sheet1

Cell Formulas
Range	Formula
H9	=IF(B9=$C$1,C9,IF(B9=$B$1,C9,IF(B9=$D$1,IF(RIGHT(C9,1)+0=4,C9+1,IF(RIGHT(C9,1)+0=6,C9+1.5,IF(RIGHT(C9,1)+0=2,C9+0.5,IF(RIGHT(C9,1)+0=0,C9)))))))

 

[sheetspread]

Excel 2010
	B	C	D	E	F	G	H	I	J	K
1	Contract	Price	BuySell		Quantity		Real Price	Crush @ fill
2	ZS	10652	Buy		10		10652.5	122.8		calculate
3	ZL	3124	Sell		9		3124
4	ZM	3838	Sell		11		3838
5	ZS	10680	Buy		10		10680	Calculate		calculate
6	ZL	3124	Sell		9		3124
7	ZM	3838	Sell		11		3838
8	ZS	10676	Buy		1		10677.5
9	ZS	10680	Buy		7		10680
10	ZS	10682	Buy		12		10682.5	calculate		calculate
11	ZL	3124	Sell		9		3124
12	ZM	3838	Sell		11		3838
13	ZS	10692	Buy		10		10692.5	calculate		calculate
14	ZL	3115	Sell		9		3115
15	ZM	3830	Sell		11		3830
16	ZS	10694	Buy		10		10695	calculate		calculate
17	ZL	3115	Sell		9		3115
18	ZM	3830	Sell		11		3830
Sheet5

Cell Formulas
Range	Formula
K2	=IF(B2<>"ZS","",IF(MOD(SUMIF($B$2:B2,"ZS",$F$2:F2),10)=0,"calculate",""))

(we can change the first row if you want)

 

[C_merr]

That's great! one more criteria i was looking for on the formula is for it to not calculate if the "real price" is the same as it was in the previous row that it calculated. is that an easy tweak on this formula?

 

[sheetspread]

wait disregard what i just wrote here if you saw it

 

[sheetspread]

Something like this depending on what goes in K2:

Excel 2010
	A	B	C	D	E	F	G	H	I	J	K
1		Contract	Price	BuySell		Quantity		Real Price	Crush @ fill
2		ZS	10652	Buy		10		10652.5	122.8		x
3		ZL	3124	Sell		9		3124
4		ZM	3838	Sell		11		3838
5		ZS	10680	Buy		10		10680	Calculate		calculate
6		ZL	3124	Sell		9		3124
7		ZM	3838	Sell		11		3838
8		ZS	10676	Buy		1		10677.5
9		ZS	10680	Buy		7		10680
10		ZS	10682	Buy		12		10682.5	calculate		calculate
11		ZL	3124	Sell		9		3124
12		ZM	3838	Sell		11		3838
13		ZS	10692	Buy		10		10692.5	calculate		calculate
14		ZL	3115	Sell		9		3115
15		ZM	3830	Sell		11		3830
16		ZS	10694	Buy		10		10695	calculate		calculate
17		ZL	3115	Sell		9		3115
18		ZM	3830	Sell		11		3830
Sheet5

Cell Formulas
Range	Formula
K3	=IF(LOOKUP(2,1/($K$1:K2<>""),$H$1:H2)=H3,"",IF(B3<>"ZS","",IF(MOD(SUMIF($B$2:B3,"ZS",$F$2:F3),10)=0,"calculate","")))