Why do so many authoritarian regimes bother with voter fraud and ballot stuffing? For example, after Hitler's annexation of Austria, intrusive propaganda and threats were used to make everybody vote for the Anschluss, but historians seem to think that the votes were correctly counted. In the case of Soviet elections, people were presented with pre-marked ballots and had to non-secretly erase the marks to vote against Communist.
More recently, Putin's United Russia party was suspected of stuffing ballots after polls are closed in remote regions of Russia, such as Chechnya.
Why did authoritarian regimes need to do this? I mean, they can easily hold a fair election without election-time fraud, completely ignore the voting results, and make up a number. They could even make up a number that looks democratic, like 58% support of the ruling party, rather than the ridiculous 99% support ratios garnered with intimidation and ballot stuffing. Electoral observers would also be satisfied. Why don't they? Do authoritarian regimes typically have weak control over the vote counting people?