As you currently have it written the district is not required to provide the para until AFTER he has written 3 lines which is why they have him sitting there waiting for a para to come help him. Is that what you want or do you want him to have the help of para available sooner? Are you comfortable with having the para (or DS) decide how much writing he should be doing? Personally I would be concerned about allowing a para who you have previously said tells your son that he should be doing more writing (i.e "You should be doing what Peter is doing") to decide if it was appropriate for him to write more than the agreed upon amount. I don't know your DS's situation, though, so it's hard for me to comment beyond that.
In our case the only people approved to have DD do more than the IEP specified amount of writing are the spec ed teacher and the OT. DD's para who really "got her" resigned last week and we don't trust the classroom teacher farther than we can throw her. For my DD the act of writing really gets in the way - it may not be as much of an issue for your DS, though. We are hoping to move more towards the keyboarding situation MoN describes but have been stymied so far on the Assistive Technology front. Your DS may be capable of more handwriting than my DD so I don't want to steer you down the wrong path.
Maybe I would consider wording more like "Developmentally appropriate lined paper will be provided for all writing tasks. DS will be encouraged to write up to 2 lines on any task independently. A scribe will be provided for any task that will require DS to write more than 3 lines. If he requests to write 4 lines or more _______" I don't know exactly what to ask for that will make you comfortable that he is actually wanting to do this extra writing and not being subtly (or not so subtly...) pushed to do it. In our case it is getting her away from her classroom and/or classroom teacher. If she makes this request in the resource room we know it is genuinely coming from DD. If it is in the classroom we believe it is most likely a result of pressure placed on her by the classroom teacher and/or wanting to do what the other kids are doing. Have you determined if there is something that your DS interprets as putting pressure on him to conform or are you comfortable that it will really be his desire to do the extra writing? If he wants to write more - are you comfortable with that or is there some reason that his written output NEEDS to be limited?
