Once again you pretend that they are equivalent. They are not. As well as both of your estimates are repugnant. It is okay to allow 5% of them to hit 20 more kids before getting caught? The average molestor has molested over 20 kids before they are caught....Man, I sure wish we could get a 98% reform rate for murder.
There is simply no "okay" amount of recidivism, and I believe that your estimates are extremely high, first because of the hidden nature of the crime and its low reporting rate, second because you just want it so bad....
No matter how "little" the recidivism there is simply no acceptable rate of recidivism for this crime.
Some crimes are just too "evil" to allow a second chance.