Weight loss shakes (like weight gain shakes) are great ways to change your weight if you're having issues with maintaining a decent diet plan. This was my biggest issue as I too was working funny hours and not always able to stick in a good routine for eating.
I tried shakes but didn't really get anything from them, other than an empty wallet
but seriously, they didn't to anything for my weight. I've hears some people get good results from them though so I might not have been using them right, although I didn't really have the budget to keep trying them out.
However I found that the best way to get my weight under control was to eat smaller meals more regularly (like 5-7 a day) and slightly increase the amount of protein I was getting. To start it didn't really matter where it was coming from but the change in diet started the process and I refined it to fit my lifestyle through trial and error.
If you do want to look at weight loss shakes, then I'd recommend getting a blender and getting some weight loss smoothie recipes (try searching on-line). This is what I do to replace breakfast sensibly as I found that it was the meal I had most problems getting regularly.
Once you get into the habit of making smoothies for shakes you'll save a bundle and get a good habit