@Des we've handled this in a few different ways depending on the needs: 1) create 3 fields for original contract value, expansion 1, expansion 2. This worked for a time when we never had more than 2 expansions on one project. 2) track additions to contracts in additional opportunities/sales orders, and then just update the project directly w/ new values. but there is a history in the transactions of the prior amounts, contracts. 3) create a custom record to store contract files & amounts, and have that as a child record to projects, with a script/workflow to populate the total contract value to the header field on the project. #3 sounds like it would fit your needs best but does require more customization (and that was just a proposed solution for us, so I can't guarantee there aren't more considerations once you actually set it up)