It’s important to realize that there are going to be unexpected consequences whenever you make a major change.
If you add a new product, it might indirectly result in a loss of sales of another one of your products (not because it cannibalizes the product but there might be a loss of focus on marketing and sales of the older product).
If you deliver your products with your own fleet, expanding your delivery system will result in higher delivery costs (that would be an expected consequence) but it might also result in having to replace your fleet sooner due to more wear and tear.
You will never be able to anticipate all consequences (if you could they wouldn’t be unexpected consequences) but it’s important to understand that you can’t panic and while you can’t anticipate all consequences, you can anticipate that you will have more then expected.
Have a great day!