The online form is probably designed as an interactive form in that your answer in one question will dictate what the next question is. The online DS 260 for immigrant visa applications is the same For example, if your marital status is single never married it’s not going to ask for your spouses details If you identified as a military personnel application, this would explain why you are only asked for one address The paper form has to cover all possibilities and applications have to complete all that is applicable to their situation and use N/A for those that don’t apply
Like other vjers ,, all the person who instructed you on this process
Don’t file both paper and online