Average, V or H lookup, match, percentage crazy formula help needed

[sycodiz]

Wondering if someone out there can help me with a crazy formula needed.

What I am trying to do:
In J, Find the audit date in A2 within c1, d1, e1, etc.
Starting with that found amount, has the amounts after steadily increased?
What percentage over the average inventory has the store increased in inventory since audit?
So row 2 I want the Increase column J to know starting at column D (since the audit date matched in C) what was the increase average each month after the audit?
In K, I would like to know what is increase % from the average inventory balance (column i) over the audit date (random column)

Any help would be greatly appreciated!

	A	B	C	D	E	F	G	H	I	J	K
1	Audit date	Mo.	Nov 17	Dec 17	Jan 18	Feb 18	Mar 18	Apr 18	Average Inventory Balance	Increase?	Increase %
2	11/27/2017	Nov 17	90,828.71	96,677.39	99,356.74	97,436.88	106,381.39	105,779.63	101,126.41
3	12/20/2017	Dec 17	88,108.74	72,260.83	76,499.91	75,206.23	74,354.31	70,069.97	73,678.25
4	11/2/2017	Nov 17	67,612.36	61,424.47	65,234.93	65,621.47	71,842.71	81,129.74	69,050.66
5	12/5/2017	Dec 17	134,051.16	137,509.69	136,774.92	136,089.10	143,397.25	157,493.94	142,252.98
6	12/13/2017	Dec 17	98,925.82	99,772.25	101,824.30	117,076.87	110,627.95	117,940.16	109,448.31

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[Eric W]

I'm not entirely clear on what you want, but try these formulas:

J2: =EXP(LN(K2+1)/(COLUMNS(C2:H2)-MATCH(A2,C$1:H$1)))-1

K2: =I2/HLOOKUP(A2,C$1:H2,ROW())-1

I'm assuming that C1:H1 are real Excel dates, set to the first of the month and formatted with the month/year.