Set rate for product + hourly rate?

[nicky]

At my web design business at inthedesigns.net, I have packages with prices set for both commercial and non-commercial users. In the packages I include a minimum amount of time that the price of the package covers, and then I start charging an additional hourly rate. This only applies to commercial users though. I was wondering if I should have the set rate for the package, but instead of working about hours, just have them pay me hourly from the beginning. So for instance, if they wanted a layout designed by me for $13, they'd be me the $13 + however many hours it took me to design it times $8 (my hourly rate) and that would be there final cost. What are your opinions? Please be honest. My price page is at www.inthedesigns.net/shop/services.php.