Multiply by days in Custom fields.

Hello, I’m trying the beta, I’ve found the new “Custom” form, I do not know if this is the name, I have it in spanish. I think it is really useful that addon, But I think that maybe you can add a option to Multiply per day, aside from adult, children and billing unit. Why? Think about a extra option for Parking. Parking costs X per day. Admins should have the option to multiply that X amount, for the amount of booking days. Does it make sense?

Thank you.

EDIT: Okay, I realized that if you choose Multiply per Billing Unit it does what I want, sorry. Next time I’ll try before posting 😉
PD: What about a number field, that user can write the quantity amount and that number will multiply the price?
For example: Do you want water on the room, if so, specify the quantity. (And now a blank box) // I know that this can be done with a drop down list, but if it isn’t hard to code it, I think that this will be useful for people.

There would happen a lot of mistakes as not all guest would understand to enter a number. For select, radio and checkboxes it’s clear what it means and intuitive to use.
Regards

Okay, better to make it consistent and with no mistakes 🙂 I’ll find another way, thanks!