Here is a way to work with reports, both standard and custom, in Google Sheets
In Manager select a report to View and then click Copy button
Open Notepad an press Ctrl-V (In Mac a comparable software would probably be TextEdit but haven’t tested)
Select Save and when entering the file name add “.htm” to the end. For example Report.htm
Open Google Sheets in a browser
File / Import / Upload / Select a file from your device
you might need to turn Amounts into numbers to work with and this can be done usually by choosing Ctrl F and replace comma (,) with dot (.)
@Lubos, export to htm button would therefore most likely be a good option to have in Manager´s Report module, to skip Notepad and copy/paste chore, as Google Sheets has become a very capable spreadsheet software.