Hi,
I have worked in executing orders in Magento for a US based e-commerce company by adding different products in their with their portal price which can also be differentiated for different customers (i.e. what they'll see if they are our active customers or just checking in without logging in).
I can effectively add the products. And if only addition of products are required and the details of the product is provided it will not take much time per product as per my experience. So, the mentioned five days with this bid is my assumption that you are asking for a good number of products for your site and for small number it may take only one day also.
Looking forward to hear from you.
Thank you.