Does the foundation laid by 'The disadvantage of this kind of machine is that it makes seams that are not as secure as the lockstitch; in addition, the appearance of the seam from the top and bottom of the fabric is different.' logically support 'This machine makes seams that are more secure than the lockstitch.'
The disadvantage of this kind of machine is that it makes seams that are not as secure as the lockstitch; in addition, the appearance of the seam from the top and bottom of the fabric is different.###This machine makes seams that are more secure than the lockstitch.