It seems to have been put there to fill the need to attribute a certain sum to marketing. Make sure you are researching each point of your budget, make sure that you are giving it context and it makes proper sense within your overall plan.
Obtain Feedback On Your Plan : When writing a business plan you sometimes end up locking yourself away. You might have unique ideas which lead you to seek some isolation and secrecy, or if you are going to be a sole trader you may only have one person to consult namely yourself. But it is fantastic to try and get broader input on your business plan - whether from a professional, or simply from friends and family whom you trust.
Research Your Competitors (But Don't Copy!) Every business plan should focus a lot on the business's potential competitors, because research and analysis of the competition effectively gives you plenty of useful information. It may guide you as to where you should be advertising and marketing, or certain strategies to use or ones to avoid because you see they have been used unsuccessfully by others.
Preparing a Business Plan: A business plan has to be in accordance with the organization in question, its situation and time. However, a business plan is not just a document to be produced and filed. Instead, business planning is a continuous process. The business plan has to be a living document, constantly in use of monitor, control and guide the progress of a business.