I am a full time Photogrpher from Italy, your prices are not too high and are actually affordable.
I charge 240€ per hour of Shooting (editing included), i usually decrease it, when they book me for longer, or don't charge every hour since i like to take my time to make the pictures as good as possible. I often also make offers which with a fixed price, for example ( i shoot picture of product A, B, C and will deliver at least 3 picture per product for X€) like this i can decide by myself how long i take for finjsbing the pictures and clients know the exact amont that i will charge already.
If you want to make a living you need to charge these prices and most of the full time photographer charge somewhere around this amount. Same as you say, about 40% of the money will be expenses and you would not always have Work. You also need to upgrade equiptment regularly to stay up to date, which cost a lot of money too and they pay for your experience which a hobby Photographer that charge less might not have.
In your situation, i would try to explain that to them. See how they react, if they try to make a big deal out of it, i would let it go and take it as a lesson for future clients. Be carefull to keep a good reputation and always give them your rates first or make an offer.
I have some, but I just give them to people when they want my contact information.
They don't have any other purpose for me.