What i meant is that you should get a recent NIW kit from any person who just got his/her NIW case approved.
The most difficult part of NIW preparation is to draft recom letters and compose your petition letter. Therefore, NIW kit from any person with similar background to yours is much more valuable than those from others.
That is my opinion for your reference.
I did not order any commercial kit from the website you mentioned. So no comments about it.