Not eveyone starts using all the availble options in Sage as soon as they purchase the package. Some grow and learn to use more of the benefits as time passes.
The 'analysis tool' is one of these extremely useful benefits.
Therefore to be able to categories historical purchase invoice entries would be useful. The benefit being that one can retrospectively allocate invoices to particular projects. Projects which may have started some time earlier.
An example being a Sage Accounting user in the construction industry who starts a building project in 2020, does not use the analysis tool. In 2021 learns how to analyses purchase invoices and would like to allocate processed invoices. These old purchase invoices from previous weeks or months have already been entered into Sage Accounting cleared through the bank feeds, reconcilled and included in a VAT Return. They cannot however be analysed as that opportunity has passed.
Retropective allocation to a poject does not have to affect any other aspect of the purchase invoice entry but would provide more relevant up-to-date and correct information.