Calculated properties for Products

We are absolutly new to Hubspot and were totally excited abou tthe product. With all the capablities, we frankly just figured this was an easy do. We sell software with Annual Maintenance and Support - the M&S is calculated as a percentage of all software line items. Then we can add things like professional services and hardware and also travel and expenses if necessary.

So I have to be able to add up all software line items, calculate M&S and then add Hardware and Profeasional Services etc. then total the quote. add tax and other fees if necessary. We have to have this feature if we are to use this platform. when will someone reply to these post please?