Can you describe a little more the workflow for creating the PDF you plan to use?
FormsCentral does not support formulas so you cannot add them in FormsCentral.
You could create a form in FormsCentral and then further edit that form in Acrobat taking care not to break the Submit (test the form after you make changes to ensure it can still submit all the data) and you could potentially add the functions there and it should work, this isn't really something we support but it should work. This FAQ tells you how to edit a FormsCentral PDF in Acrobat: http://forums.adobe.com/docs/DOC-3661
You can also create a form outside of FormsCentral and Import the PDF into FormsCentral that has the calculations already built in, no guarantee but it should work as well.
You said "embedded into an online PDF form" - we strongly recommend against embedding a PDF into a web page, or having a FormsCentral PDF open in the browser as you cannot control the PDF viewer that will be used to fill/submit the PDF and any viewer other than Adobe Reader/Acrobat will break a FormsCentral PDF, see this FAQ for more details: http://forums.adobe.com/docs/DOC-4142
Let me tell you what I am sure about and what I am not sure about:
I am sure that I want to be able to sell my products online. The industrial market that I sell to usually do not allow the maintenance people that find me on the web, do not have the ability to use credit cards in a typical shopping cart format due to the higher prices that the equipment I sell costs and that most people call me up to 'request a formal quotation' to give to their purchasing depart. So, my bright idea is to create numerous pdf files with very specific url's to match the very specific items that I sell. (1) item per pdf. I am thinking that the advantage to skipping the shopping cart approach and allowing the customer to fill in the qty of items, which would be mulitpled by the price of the item (a constant #) and then hitting a apply button, that would calculate subtotal price. Discounts for the qty the customer inputs (qty of items inputted by customer would be discounted on a percentage x base price) and a refresh the screen. It would allow for SEO advantages from what I have seen in the past in my very vertical market. All forms would be setup using the same functionality, just images, alt text, urls, and readable text would change.
What I don't know- which is alot, then how to calculate shipping costs. I have a weight per item, which can be added up. I saw an Adobe blog that allows UPS shipping cost to be programmed in. I don't know how dreamweaver works, which was what the blog mentioned would allow for this updated, instantanious interface with UPS and calculating real shipping costs to a specific zip code. Shipping cost would be fluff to this page. The main thing would be to do allow the customer to be able to fill in a qty of the specific item on the page, calculate a discount if / then type thing, be able to have customer email to purchasing dept or print. I would date stamp it with verbage that pricing is valid for XX days and if I could get a copy emailed to me that would be icing on the cake. I believe that this non static pdf would be something different then the current competion and that it would allow for 100's of quotes to be generated without customers having to wait 15 minutes to an hour for me to process the exact document that they are looking for.
You can choose to use FormsCentral as part of your work flow and collect responses in FormsCentral which enables you to set up things like Email Reciepts and Email Notifications that can include the forms data.
Whether you use FormsCentral to collect and manage the responses or not, everything related to calculations would be outside of FormsCentral support and would require you to go the Acrobat Forms Forums to figure out how to configure it all. Once configured you can test the PDF with FormsCentral and double check everything works as expected.
You can create a form in FormsCentral that has the fields you'd like in the PDF, save as a PDF and then follow the FAQ I referenced for how to edit in Acrobat, and utilize the Acrobat Forms Forums to add the formulas to the fields in the PDF, and then test Submitting the form after filling it out several times to ensure it works as you expect.
As far as placing the PDF online to be filled out in a web browser, please refer to the FAQ I linked to where we recommend against doing that with a FormsCentral PDF.
OK Thanks- Need to do alot of thinking about this, Thanks for the timely and wise advise. Over and Out for now.