Still, I have to report a few hundred posts more and I can reach the 100% accuracy again (e.g. 10 bad vs. 1001 good, that's only 0,99999999% bad, hopefully 100% good 
).
).You are correct. The reporting accuracy always rounds up, so 99.00001% will be reported as 100%. Given you have made 10 bad reports, making 991 good would mean 991/1001 were good (99.0001%), and your accuracy would read 100%. Broadly speaking, you can make 1 bad report for every 100 good ones that you make and still maintain 100% accuracy.