How do I distribute a new total budget amount proportionally to the nearest thousandth?

[carolinemarie]

I'm trying to solve a problem for work and I'm wracking my brain on how to do it.
Here's the background. I have 10 campaigns each varying in a percentage of the total budget. The client is reducing the budget by $1,700 for the next quarter. I could subtract each of the 10 budgets by $170 or I could take the campaign percentage of the new total budget but the problem is each budget results in an exact number instead of a number rounded to the nearest thousandth like the original number.

Here's the an example of what I mean in excel:

It doesn't have to be the exact percentage of the original campaign- as long as it's somewhat near it. How would I distribute the new total budget to the nearest thousandth across the 10 campaigns- in close range of the original percentage?

I should also note, I get in some circumstances, rounding to the nearest hundredth might be necessary to sum up to the total budget, like in F6, but the general preference is to have the budget to the nearest thousandth.

I appreciate any help!

 

[shinigamilight]

I presume something like this

=CEILING(B1,100)

 

[Dave Patton]

T202212a.xlsm
	A	B	C	D	E	F	G	H	I	J	K	L	M
6		Budget	45,000	15,000	45,000	14,700	20,000	27,000	3,000	10,000	10,000	10,000	199,700
7			44,600	14,900	44,600	14,600	19,800	26,800	3,000	9,900	9,900	9,900	198,000
8
2e

Cell Formulas
Range	Formula
M6:M7	M6	=SUM(C6:L6)
C7:L7	C7	=ROUND(198000/199700*C6,-2)

T202212a.xlsm
	B	C	D	E	F	G	H	I	J	K	L	M
6	Budget	45,000	15,000	45,000	14,700	20,000	27,000	3,000	10,000	10,000	10,000	199,700
7		1,000	0	1,000	0	0	0	0	0	0	0	2,000
8		44,000	15,000	44,000	14,700	20,000	27,000	3,000	10,000	10,000	10,000	197,700
2e

Cell Formulas
Range	Formula
M6:M8	M6	=SUM(C6:L6)
C7:L7	C7	=CEILING((MAX($C$6:$L$6)=C6)*0.5*$C$3,1000)
C8:L8	C8	=C6-C7

 

[shinigamilight]

I presume something like this

=CEILING(B1,100)

=MROUND(B1,100)
You can use either of the two whichever fits your description.

 

[Dave Patton]

T202212a.xlsm
	B	C	D	E	F	G	H	I	J	K	L	M
6	Budget	45000	15000	45000	14700	20000	27000	3000	10000	10000	10000	199700
7		44600	14900	44600	14600	19800	26800	3000	9900	9900	9900	198000
8	Round	1000	0	1000	0	0	0	0	0	0	0
9	Revised	44000	15000	44000	14700	20000	27000	3000	10000	10000	10000	197700
2e

Cell Formulas
Range	Formula
M9,M6:M7	M6	=SUM(C6:L6)
C7:L7	C7	=ROUND(198000/199700*C6,-2)
C8:L8	C8	=ROUND((C6-C7)*2,-3)
C9:L9	C9	=C6-C8