Every state has its own sex offender registry with its own registration statute and its own set of rules. Many of the state statutes and state rules sort of look alike. One reason for this is that there is federal legislation in the Adam Walsh Act that told the U.S.Justice Department to come up with a model set of regulations or minimum standards that states have to comply with if they wanted money.
States more or less have chosen to comply with some or all of the federal regulations. Iowa has adopted some portion of those regulations. The tier system of classifying offenses that is used in Iowa is a reflection of the federal guidelines.
In other areas, Iowa has not, however, adopted or brought its statute in compliance with Adam Walsh. This is true with regard to the length of registration. The length of registration is much longer under Adam Walsh than it is in Iowa under the Iowa statute. It seems to me that part of the reason is that there is not that much money available from the federal government if there is compliance.
This is a long introduction to the important practical point that every state is different. This can include how much information you have to provide to the registry, how individuals with juvenile adjudications are treated, what kinds of restrictions there are on where you live and what kinds of work you can do, and perhaps most importantly the length of registration.
If you have a conviction from Iowa, you need to understand that if you go to another state you are going to be subjected to the laws in that state, not Iowa. If the length of registration is longer in the state you move to, you will be subject to the longer period of registration. If you modified off the registry in Iowa, you may still have to register in the new state. If you complete your ten years of registration, you may still have to register in the new state.
The unfortunate reality is that you can come off the registry in Iowa but might still have to register or be subject to the registration requirements in another state. The practical pointer is that if you are thinking about moving to another state, or working in another state, or spending significant time in another state, and you are a sex offender or had a sex offense in the past, you need to talk to a lawyer about the rules in the other jurisdiction.