Identify the differences between 2 tables

HI Mederic 

Download example PBIX file

After importing both tables you can Append them.

Then Group by ID and choose Sum as the aggregation.

Then remove Amounts you don't want

Here's the query for the merge onwards

let
    Source = Table.Combine({Table1, Table2}),
    #"Grouped Rows" = Table.Group(Source, {"ID"}, {{"Sum", each List.Sum([Amount]), type nullable number}}),
    #"Filtered Rows" = Table.SelectRows(#"Grouped Rows", each [Sum] >= 0.2 or [Sum] <= -0.2)
in
    #"Filtered Rows"

I nortice that in your result you've got the Amount 58.56 for the ID 58, rather than the difference between the 2 amounts.

If you want to have this Amount from Table1, do a merge with my result table and Table1 to pull in the desired Amount, then delete unwanted columns.

Regards

Phil