Slow reaction whilst 'tabbing' through a form

We have created a form which is a way of recording a list of passenger details, for each passenger there are 4 fields and we are allowing for up to 80 passengers.

Whether these form elements show is also dependent on a radio button having a certain value so each Passenger field has a related conditional attached.

Now the issue is when client chooses the radio button that does not show the passenger fields there is about up to a 25 second delay before the form reacts and takes the user to the signature panel.

Is this purely a numbers issue – so many conditionals to work out (320 individual elements) before it can move? Or is there something else?

Your help would be appreciated

Thanks

John