straightening a wall in exteneded bedroom help?

My builder built extension at end of bungalow before breaking through the end wall to in effect extend the bedroom by 12 foot. When he builit on of the extended end walls this wall was in effect in middle and when he finally demoliahed the old end wall the new middle wall did not match up exactly. He has now suggested that to make the wall straight he will put a slab of plasterboard up against what was the old wall. I thought nothing of this suggestion and agreed but he was not very clever when it came to putting in my stud partions so I am wondering if he is pulling the wool over my eyes again. I am now thinking there may be another option but cant for the life of me see it or I could live with a out of kilter wall but it woould be obivious as you walked in as the bed will be up against it.

Help
noah

It's common practice to dryline over the junction of new to old construction- it helps to counteract shrinkage cracking and helps to disguise what would otherwise be an obvious "construction joint".

thanks but he is only dry lining on the old wall to bring it level with new, ie joint will be as is just plastered.

noah