First, they drew up the percentages and only then calculated the absolute numbers. When votes are counted, rather than results fabricated, the process should be the other way around.

Briefly on Romania's 2014 Presidential Election 1st Round
Wikipedia article.

Briefly on Turkey's 2014 Presidential Election
Wikipedia article.

The election results in Syria are just as fabricated as those in Luhansk. The organisers also calculated the number of voters based on predetermined percentages. 

It can be considered proven that the "results" of the referendum, at least in the Luhansk region, were determined arbitrarily by its organizers, without any connection to the actual voting results.

When results are fabricated, percentages are first made up, and absolute numbers are then calculated from them. That's how they got caught.

Summary of Azerbaijan Presidential Election 2013

Wikipedia article.