Hello we are a small construction company but undertake some fairly large projects.
We may have a fixed price on a project that could last a year or more. We do fortnightly or monthly valuations and invoice according to what has been done over that period. Materials and labour charges will vary dramatically month on month but would like to show each invoice deducting from the initial price and also have the option to add additional extra items that have not been priced for originally.
Any info on how to do this would be very grateful or do I need to use a different product?