Page allignment is one of key element to get an excellent recognition rate. The area are defined on a template form so its evident that they could be result disalligned, in horzontal and/or in vertical, on forms to recognize for the scanning operation that introduces a variable offset.
You can define several allignment strategies looking at form type. If the form was designed for data catpure it with great probability will have some allignment black boxes in the four corners: in this case this boxes are enough to calculate the form offest respect to template form so that recognition area are corrected accordling.
If the form don't includes allignment boxes you can still choice between two solutions: the search of dominant lines or the allignment of full preprinted part of form. You should use the first solution if the forms to process are form printed with not blind ink and if the form includes some well defined horizontal and vertical lines. You should use the second solution for all other cases if the static elements present on template form are present also on forms to process.
In every case to get a corret allignment you have to be sure that the page is strenght, so you have to use the function of global Deskew on the full image.