OFFICE-3920 VDB startPeriod and endPeriod

[Regina Henschel <regina.henschel@libreoffice.org>]

Hi all,

the attached spreadsheet contains the way LibreOffice calculates VDB 
with startPeriod and endPeriod with fractions.

If e.g. startPeriod is 4.75 and endPeriod is 9.75 then LibreOffice does: 
Calculate VDB for 4 to 5 and take *0.25 from that value.
Calculate VDB for 5 to 9.
Calculate VDB for 9 to 10 and take *0.75 from that value.
Sum the three values.

The spreadsheet contains a section, where I do these three steps 
separately and sum the results and below a line, where I call VDB on the 
entire time interval. The calculation is done with switch to 
straight-line depreciation and without switch.

You should test it in other applications to see, whether LibreOffice's 
way is common. Then we can formulate it for the spec.

Kind regards
Regina

Attachment: FractionalVDB.ods
Description: application/vnd.oasis.opendocument.spreadsheet