It can certainly help. You're fortunate in the sense that you have some historical data to compare against. It may be helpful to examine this data. Putting it all together in a business plan might not only help you identify the areas that need to be addressed, but you can also base some assumptions on how that situation may change by creating some forward-looking forecasts.
Also, if you find yourself in financial need from a bank or other capital source, they will likely want to see a business plan to gain insight and to consider the steps you've identified to remedy the situation.