Multiply values in column by a number if a date is detected as the column name in Power Query.

[programsam]

I'm attempting to have Power Query parse a list of columns and if the column has a month name as a header, I'd like to have it multiply the values in that column by 1.1 (10% increase). Here's my best attempt but it's giving me an error.

= Table.ReplaceValue(#"Renamed Columns", each try Value.Is(Date.From(_), type date), each (_) * 1.1, Replacer.ReplaceValue, {_})

 

[JGordon11]

let
    Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
    months = List.Transform({1..12}, each Date.MonthName(#date(2023,_,1))),
    tcn = Table.ColumnNames(Source),
    MonthCols = List.Select(tcn, each List.Contains(months,_)),
    TransformOps = List.Accumulate(MonthCols, {}, (s,c)=> s & {{c, each _*1.1}}),
    Result = Table.TransformColumns(Source, TransformOps)
in
    Result

Book1
	A	B	C	D	E	F	G	H	I	J	K	L	M	N
1	Column1	Column2	Column3	January	February	March		Column1	Column2	Column3	January	February	March
2	30	22	24	12	39	29		30	22	24	13.2	42.9	31.9
3	1	27	28	40	2	13		1	27	28	44.0	2.2	14.3
4	26	23	11	42	37	32		26	23	11	46.2	40.7	35.2
5	35	9	38	17	25	41		35	9	38	18.7	27.5	45.1
6	33	6	10	16	4	14		33	6	10	17.6	4.4	15.4
7	15	19	21	18	8	20		15	19	21	19.8	8.8	22.0
8	5	34	36	7	31	3		5	34	36	7.7	34.1	3.3
9
Sheet2