We recently purchased the Chicco Kidfit booster seat for our 4 year old. She is too tall for her convertible car seat. We are having an issue with the shape of the rear seats in the MS. The contour of the back seat and headrest create a gap between the back of the booster seat and the MS's rear seat (see attached photo from booster seat manual). Does anyone have children in the 4-8 year range and use a booster seat with a back? If so, please let us know how you solved this problem! Any recommendations of children's booster seats that fit the rear seats of the MS? Thanks!