Total amount of what ? Have you try before answering the questions ? There is nothing related with the invoice price on those report !

it is based on account_invoice_line report, its the total of invoice line sub total field without include tax

I am still not clear with your answer, if it represent the number of invoice line why can I have a decimal value on those column ? As an example I get this value on the report : All product / Saleable (8), number of line : 8, Qty : 19.00, Total without tax : 19.29 I intrepret those as the total number of invoice line of all saleable product is 8 line, the quantity on those 8 line is 19, but what is 19.29 ? Is it the total number of subtotal field without tax ? What is the meaning of the decimal point ?

Yes it is subtotal of invoice line without tax.

It means (in the example I wrote above) there is 19.29 invoice line (without tax). What is 0.29 invoice line means ? Where is this number came from ?

The numbers it seems to be wrong summarized, if you ask for groupong the data by: product, Customer, type, it gives you wrong data

Ok I checked the code account_invoice_report.py of account module that tries to get the currency of the user with condition rate = 1 that means that you must check that your base currency have the rate = 1 and the value of the report will give to you the right value of Total without tax other way you will receive fake values i think this check it most be changed on code to looking for base currency instead of rate = 1 because it could take fake values.