Due to the logic contained within the turnover reports and the headcount reports, they can display different values despite seemingly retrieving the same information on the same day.
Turnover reports will retrieve 'heads' data from the very beginning and the very end of the day, whereas the Headcount report will retrieve a general overview of the day, depending on the information visible in the 'Current Positions with organisation As At Evaluation Date' View.
As an example of different data being viewed, a headcount report was run from 01/01/2017 - 01/01/2017 (One day) and displayed 95 days heads at start and 100 days heads at end.
A headcount report run on the date of 01/01/2017 will show 100 as this takes a full view of the entire day.
A method of getting a spanning turnover report to show the completed day's result such as 1st Jan 2017 to 31st Dec 2018 would be to start the turnover report one day later e.g. 2nd Jan 2017 - 31st Dec as this would contain the 1st of Jan's end-of-day data and be before the 2nd of Jan headcount data begins.
Custom headcount reports
While it is possible to export on the same view that the system reports use, quite often your requirements will not be met by this view, as most of our customers tend to have different requirements.
As such, it is recommended that if the standard headcount reports do not meet your needs, you request a customised headcount report by contacting your account manager. This would likely incur a cost, so bear this in mind when considering a custom report.