Quote from sle:
Of course it has to be low, otherwise nobody would buy this crap. You can't charge more then a couple hundred bucks for something that simple. I am willing to bet that if you use your hoadley add-in and calculate implied volatilities for S&P, for example, even the put/call vol equality is not going to hold. Not trying to discredit his tools, but for simply punting delta you can write your own simple spreadsheet (oh, yeah, VBA for black/scholes and simple prop-div binomial is out there for free) or use the tools provided by the broker. Most probably the implied volatility numbers and risks are going to be significantly wrong either way.
PS. I am not, by any means, involved in sales of trading software.