Having an accurate title is useful for the reader to understand what they are looking at. For example the title "purchase agreement" is confusing for the reader if there are two parties - a purchaser and a seller. Revising the title to Purchase and Sale Agreement would clarify. However and in addition, a "purchase and sale agreement" is commonly used to describe a sale of major assets, or even a business. So it would be useful to clarify in the agreement title that this agreement is the "Purchase and Sale of a Product", or "Purchase and Sale of a Specific Product", or "Purchase and Sale of a business", whichever should apply.