I have multiple events in the same category with different event ticket base prices. I would like to add an item selection in the registration page for each event in that category that results in a surcharge being applied to the base ticket price and incorporate that surcharge in the final price (as a percent of the event fee) rather than as a fixed fee.
For example, if the event ticket is $50, "priority access" would result in the total cost being 20% higher or $60. If the event ticket is $40, the priority access would result in a total fee of $48.
If I create a custom field for "priority access" so that it appears in the registration form, it appears my only option for the added cost is to set a fixed price. With that limitation, I would need to have a separate and unique custom field for every surcharge amount rather than a single custom field for the category. Am I missing an option for setting the fee field as a multiplier of the event ticket fee? If not, is there a workaround?
I didn't see that in the documentation. Searching for the [INDIVIDUAL_PRICE] variable now, I only found it mentioned in the Invoice section. Perhaps it could also be discussed in the Custom Fee portion of the documentation.